 bfcd062e8e
			
		
	
	bfcd062e8e
	
	
	
		
			
			We currently ask for anything above 3.2 GL contexts, but we're still using GLSL 1.50 shaders all over the place. If a GL driver supports GL 3.2+ and GLSL 1.50 only then we'd be in trouble, but the chances of that happening are really small.
		
			
				
	
	
		
			963 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			963 lines
		
	
	
		
			26 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* The rendering code in here is taken from es2gears, which has the
 | |
|  * following copyright notice:
 | |
|  *
 | |
|  * Copyright (C) 1999-2001  Brian Paul   All Rights Reserved.
 | |
|  *
 | |
|  * Permission is hereby granted, free of charge, to any person obtaining a
 | |
|  * copy of this software and associated documentation files (the "Software"),
 | |
|  * to deal in the Software without restriction, including without limitation
 | |
|  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 | |
|  * and/or sell copies of the Software, and to permit persons to whom the
 | |
|  * Software is furnished to do so, subject to the following conditions:
 | |
|  *
 | |
|  * The above copyright notice and this permission notice shall be included
 | |
|  * in all copies or substantial portions of the Software.
 | |
|  *
 | |
|  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 | |
|  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 | |
|  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 | |
|  * BRIAN PAUL BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
 | |
|  * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 | |
|  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 | |
|  *
 | |
|  * Ported to GLES2.
 | |
|  * Kristian Høgsberg <krh@bitplanet.net>
 | |
|  * May 3, 2010
 | |
|  *
 | |
|  * Improve GLES2 port:
 | |
|  *   * Refactor gear drawing.
 | |
|  *   * Use correct normals for surfaces.
 | |
|  *   * Improve shader.
 | |
|  *   * Use perspective projection transformation.
 | |
|  *   * Add FPS count.
 | |
|  *   * Add comments.
 | |
|  * Alexandros Frantzis <alexandros.frantzis@linaro.org>
 | |
|  * Jul 13, 2010
 | |
|  */
 | |
| 
 | |
| #include "config.h"
 | |
| 
 | |
| #include <math.h>
 | |
| #include <stdlib.h>
 | |
| #include <string.h>
 | |
| #include <epoxy/gl.h>
 | |
| 
 | |
| #include "gtkgears.h"
 | |
| 
 | |
| #define STRIPS_PER_TOOTH 7
 | |
| #define VERTICES_PER_TOOTH 34
 | |
| #define GEAR_VERTEX_STRIDE 6
 | |
| 
 | |
| #ifndef HAVE_SINCOS
 | |
| static void
 | |
| sincos (double x, double *_sin, double *_cos)
 | |
| {
 | |
|   *_sin = sin (x);
 | |
|   *_cos = cos (x);
 | |
| }
 | |
| #endif
 | |
| 
 | |
| /**
 | |
|  * Struct describing the vertices in triangle strip
 | |
|  */
 | |
| struct vertex_strip {
 | |
|    /** The first vertex in the strip */
 | |
|    GLint first;
 | |
|    /** The number of consecutive vertices in the strip after the first */
 | |
|    GLint count;
 | |
| };
 | |
| 
 | |
| /* Each vertex consist of GEAR_VERTEX_STRIDE GLfloat attributes */
 | |
| typedef GLfloat GearVertex[GEAR_VERTEX_STRIDE];
 | |
| 
 | |
| /**
 | |
|  * Struct representing a gear.
 | |
|  */
 | |
| struct gear {
 | |
|    /** The array of vertices comprising the gear */
 | |
|    GearVertex *vertices;
 | |
|    /** The number of vertices comprising the gear */
 | |
|    int nvertices;
 | |
|    /** The array of triangle strips comprising the gear */
 | |
|    struct vertex_strip *strips;
 | |
|    /** The number of triangle strips comprising the gear */
 | |
|    int nstrips;
 | |
| };
 | |
| 
 | |
| typedef struct {
 | |
|   /* The view rotation [x, y, z] */
 | |
|   GLfloat view_rot[GTK_GEARS_N_AXIS];
 | |
| 
 | |
|   /* The Vertex Array Object */
 | |
|   GLuint vao;
 | |
| 
 | |
|   /* The shader program */
 | |
|   GLuint program;
 | |
| 
 | |
|   /* The gears */
 | |
|   struct gear *gear1;
 | |
|   struct gear *gear2;
 | |
|   struct gear *gear3;
 | |
| 
 | |
|   /** The Vertex Buffer Object holding the vertices in the graphics card */
 | |
|   GLuint gear_vbo[3];
 | |
| 
 | |
|   /** The location of the shader uniforms */
 | |
|   GLuint ModelViewProjectionMatrix_location;
 | |
|   GLuint NormalMatrix_location;
 | |
|   GLuint LightSourcePosition_location;
 | |
|   GLuint MaterialColor_location;
 | |
| 
 | |
|   /* The current gear rotation angle */
 | |
|   GLfloat angle;
 | |
| 
 | |
|   /* The projection matrix */
 | |
|   GLfloat ProjectionMatrix[16];
 | |
| 
 | |
|   /* The direction of the directional light for the scene */
 | |
|   GLfloat LightSourcePosition[4];
 | |
| 
 | |
|   gint64 first_frame_time;
 | |
|   guint tick;
 | |
|   GtkLabel *fps_label;
 | |
| } GtkGearsPrivate;
 | |
| 
 | |
| G_DEFINE_TYPE_WITH_PRIVATE (GtkGears, gtk_gears, GTK_TYPE_GL_AREA)
 | |
| 
 | |
| static gboolean gtk_gears_render        (GtkGLArea     *area,
 | |
|                                          GdkGLContext  *context);
 | |
| static void     gtk_gears_reshape       (GtkGLArea     *area,
 | |
|                                          int            width,
 | |
|                                          int            height);
 | |
| static void     gtk_gears_realize       (GtkWidget     *widget);
 | |
| static void     gtk_gears_unrealize     (GtkWidget     *widget);
 | |
| static gboolean gtk_gears_tick          (GtkWidget     *widget,
 | |
|                                          GdkFrameClock *frame_clock,
 | |
|                                          gpointer       user_data);
 | |
| 
 | |
| static void destroy_gear (struct gear *g);
 | |
| 
 | |
| GtkWidget *
 | |
| gtk_gears_new (void)
 | |
| {
 | |
|   return g_object_new (gtk_gears_get_type (),
 | |
|                        "has-depth-buffer", TRUE,
 | |
|                        NULL);
 | |
| }
 | |
| 
 | |
| static void
 | |
| gtk_gears_init (GtkGears *gears)
 | |
| {
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
| 
 | |
|   priv->view_rot[GTK_GEARS_X_AXIS] = 20.0;
 | |
|   priv->view_rot[GTK_GEARS_Y_AXIS] = 30.0;
 | |
|   priv->view_rot[GTK_GEARS_Z_AXIS] = 20.0;
 | |
| 
 | |
|   priv->LightSourcePosition[0] = 5.0;
 | |
|   priv->LightSourcePosition[1] = 5.0;
 | |
|   priv->LightSourcePosition[2] = 10.0;
 | |
|   priv->LightSourcePosition[3] = 1.0;
 | |
| 
 | |
|   priv->tick = gtk_widget_add_tick_callback (GTK_WIDGET (gears), gtk_gears_tick, gears, NULL);
 | |
| }
 | |
| 
 | |
| static void
 | |
| gtk_gears_finalize (GObject *obj)
 | |
| {
 | |
|   GtkGears *gears = GTK_GEARS (obj);
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
| 
 | |
|   gtk_widget_remove_tick_callback (GTK_WIDGET (gears), priv->tick);
 | |
| 
 | |
|   g_clear_object (&priv->fps_label);
 | |
| 
 | |
|   g_clear_pointer (&priv->gear1, destroy_gear);
 | |
|   g_clear_pointer (&priv->gear2, destroy_gear);
 | |
|   g_clear_pointer (&priv->gear3, destroy_gear);
 | |
| 
 | |
|   G_OBJECT_CLASS (gtk_gears_parent_class)->finalize (obj);
 | |
| }
 | |
| 
 | |
| static void
 | |
| gtk_gears_class_init (GtkGearsClass *klass)
 | |
| {
 | |
|   GTK_GL_AREA_CLASS (klass)->render = gtk_gears_render;
 | |
|   GTK_GL_AREA_CLASS (klass)->resize = gtk_gears_reshape;
 | |
| 
 | |
|   GTK_WIDGET_CLASS (klass)->realize = gtk_gears_realize;
 | |
|   GTK_WIDGET_CLASS (klass)->unrealize = gtk_gears_unrealize;
 | |
| 
 | |
|   G_OBJECT_CLASS (klass)->finalize = gtk_gears_finalize;
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * Fills a gear vertex.
 | |
|  *
 | |
|  * @param v the vertex to fill
 | |
|  * @param x the x coordinate
 | |
|  * @param y the y coordinate
 | |
|  * @param z the z coortinate
 | |
|  * @param n pointer to the normal table
 | |
|  *
 | |
|  * @return the operation error code
 | |
|  */
 | |
| static GearVertex *
 | |
| vert (GearVertex *v,
 | |
|       GLfloat x,
 | |
|       GLfloat y,
 | |
|       GLfloat z,
 | |
|       GLfloat n[3])
 | |
| {
 | |
|   v[0][0] = x;
 | |
|   v[0][1] = y;
 | |
|   v[0][2] = z;
 | |
|   v[0][3] = n[0];
 | |
|   v[0][4] = n[1];
 | |
|   v[0][5] = n[2];
 | |
| 
 | |
|   return v + 1;
 | |
| }
 | |
| 
 | |
| static void
 | |
| destroy_gear (struct gear *g)
 | |
| {
 | |
|   g_free (g->strips);
 | |
|   g_free (g);
 | |
| }
 | |
| 
 | |
| /**
 | |
|  *  Create a gear wheel.
 | |
|  *
 | |
|  *  @param inner_radius radius of hole at center
 | |
|  *  @param outer_radius radius at center of teeth
 | |
|  *  @param width width of gear
 | |
|  *  @param teeth number of teeth
 | |
|  *  @param tooth_depth depth of tooth
 | |
|  *
 | |
|  *  @return pointer to the constructed struct gear
 | |
|  */
 | |
| static struct gear *
 | |
| create_gear (GLfloat inner_radius,
 | |
|              GLfloat outer_radius,
 | |
|              GLfloat width,
 | |
|              GLint teeth,
 | |
|              GLfloat tooth_depth)
 | |
| {
 | |
|   GLfloat r0, r1, r2;
 | |
|   GLfloat da;
 | |
|   GearVertex *v;
 | |
|   struct gear *gear;
 | |
|   double s[5], c[5];
 | |
|   GLfloat normal[3];
 | |
|   int cur_strip = 0;
 | |
|   int i;
 | |
| 
 | |
|   /* Allocate memory for the gear */
 | |
|   gear = g_malloc (sizeof *gear);
 | |
| 
 | |
|   /* Calculate the radii used in the gear */
 | |
|   r0 = inner_radius;
 | |
|   r1 = outer_radius - tooth_depth / 2.0;
 | |
|   r2 = outer_radius + tooth_depth / 2.0;
 | |
| 
 | |
|   da = 2.0 * M_PI / teeth / 4.0;
 | |
| 
 | |
|   /* Allocate memory for the triangle strip information */
 | |
|   gear->nstrips = STRIPS_PER_TOOTH * teeth;
 | |
|   gear->strips = g_malloc0_n (gear->nstrips, sizeof (*gear->strips));
 | |
| 
 | |
|   /* Allocate memory for the vertices */
 | |
|   gear->vertices = g_malloc0_n (VERTICES_PER_TOOTH * teeth, sizeof(*gear->vertices));
 | |
|   v = gear->vertices;
 | |
| 
 | |
|   for (i = 0; i < teeth; i++) {
 | |
|     /* A set of macros for making the creation of the gears easier */
 | |
| #define  GEAR_POINT(p, r, da) do { p.x = (r) * c[(da)]; p.y = (r) * s[(da)]; } while(0)
 | |
| #define  SET_NORMAL(x, y, z) do { \
 | |
|    normal[0] = (x); normal[1] = (y); normal[2] = (z); \
 | |
| } while(0)
 | |
| 
 | |
| #define  GEAR_VERT(v, point, sign) vert((v), p[(point)].x, p[(point)].y, (sign) * width * 0.5, normal)
 | |
| 
 | |
| #define START_STRIP do { \
 | |
|    gear->strips[cur_strip].first = v - gear->vertices; \
 | |
| } while(0);
 | |
| 
 | |
| #define END_STRIP do { \
 | |
|    int _tmp = (v - gear->vertices); \
 | |
|    gear->strips[cur_strip].count = _tmp - gear->strips[cur_strip].first; \
 | |
|    cur_strip++; \
 | |
| } while (0)
 | |
| 
 | |
| #define QUAD_WITH_NORMAL(p1, p2) do { \
 | |
|    SET_NORMAL((p[(p1)].y - p[(p2)].y), -(p[(p1)].x - p[(p2)].x), 0); \
 | |
|    v = GEAR_VERT(v, (p1), -1); \
 | |
|    v = GEAR_VERT(v, (p1), 1); \
 | |
|    v = GEAR_VERT(v, (p2), -1); \
 | |
|    v = GEAR_VERT(v, (p2), 1); \
 | |
| } while(0)
 | |
|     struct point {
 | |
|       GLfloat x;
 | |
|       GLfloat y;
 | |
|     };
 | |
| 
 | |
|     /* Create the 7 points (only x,y coords) used to draw a tooth */
 | |
|     struct point p[7];
 | |
| 
 | |
|     /* Calculate needed sin/cos for varius angles */
 | |
|     sincos(i * 2.0 * G_PI / teeth + da * 0, &s[0], &c[0]);
 | |
|     sincos(i * 2.0 * M_PI / teeth + da * 1, &s[1], &c[1]);
 | |
|     sincos(i * 2.0 * M_PI / teeth + da * 2, &s[2], &c[2]);
 | |
|     sincos(i * 2.0 * M_PI / teeth + da * 3, &s[3], &c[3]);
 | |
|     sincos(i * 2.0 * M_PI / teeth + da * 4, &s[4], &c[4]);
 | |
| 
 | |
|     GEAR_POINT(p[0], r2, 1);
 | |
|     GEAR_POINT(p[1], r2, 2);
 | |
|     GEAR_POINT(p[2], r1, 0);
 | |
|     GEAR_POINT(p[3], r1, 3);
 | |
|     GEAR_POINT(p[4], r0, 0);
 | |
|     GEAR_POINT(p[5], r1, 4);
 | |
|     GEAR_POINT(p[6], r0, 4);
 | |
| 
 | |
|     /* Front face */
 | |
|     START_STRIP;
 | |
|     SET_NORMAL(0, 0, 1.0);
 | |
|     v = GEAR_VERT(v, 0, +1);
 | |
|     v = GEAR_VERT(v, 1, +1);
 | |
|     v = GEAR_VERT(v, 2, +1);
 | |
|     v = GEAR_VERT(v, 3, +1);
 | |
|     v = GEAR_VERT(v, 4, +1);
 | |
|     v = GEAR_VERT(v, 5, +1);
 | |
|     v = GEAR_VERT(v, 6, +1);
 | |
|     END_STRIP;
 | |
| 
 | |
|     /* Inner face */
 | |
|     START_STRIP;
 | |
|     QUAD_WITH_NORMAL(4, 6);
 | |
|     END_STRIP;
 | |
| 
 | |
|     /* Back face */
 | |
|     START_STRIP;
 | |
|     SET_NORMAL(0, 0, -1.0);
 | |
|     v = GEAR_VERT(v, 6, -1);
 | |
|     v = GEAR_VERT(v, 5, -1);
 | |
|     v = GEAR_VERT(v, 4, -1);
 | |
|     v = GEAR_VERT(v, 3, -1);
 | |
|     v = GEAR_VERT(v, 2, -1);
 | |
|     v = GEAR_VERT(v, 1, -1);
 | |
|     v = GEAR_VERT(v, 0, -1);
 | |
|     END_STRIP;
 | |
| 
 | |
|     /* Outer face */
 | |
|     START_STRIP;
 | |
|     QUAD_WITH_NORMAL(0, 2);
 | |
|     END_STRIP;
 | |
| 
 | |
|     START_STRIP;
 | |
|     QUAD_WITH_NORMAL(1, 0);
 | |
|     END_STRIP;
 | |
| 
 | |
|     START_STRIP;
 | |
|     QUAD_WITH_NORMAL(3, 1);
 | |
|     END_STRIP;
 | |
| 
 | |
|     START_STRIP;
 | |
|     QUAD_WITH_NORMAL(5, 3);
 | |
|     END_STRIP;
 | |
|   }
 | |
| 
 | |
|   gear->nvertices = (v - gear->vertices);
 | |
| 
 | |
|   return gear;
 | |
| }
 | |
| 
 | |
| /** 
 | |
|  * Multiplies two 4x4 matrices.
 | |
|  *
 | |
|  * The result is stored in matrix m.
 | |
|  *
 | |
|  * @param m the first matrix to multiply
 | |
|  * @param n the second matrix to multiply
 | |
|  */
 | |
| static void
 | |
| multiply (GLfloat *m, const GLfloat *n)
 | |
| {
 | |
|    GLfloat tmp[16];
 | |
|    const GLfloat *row, *column;
 | |
|    div_t d;
 | |
|    int i, j;
 | |
| 
 | |
|    for (i = 0; i < 16; i++) {
 | |
|       tmp[i] = 0;
 | |
|       d = div(i, 4);
 | |
|       row = n + d.quot * 4;
 | |
|       column = m + d.rem;
 | |
|       for (j = 0; j < 4; j++)
 | |
|          tmp[i] += row[j] * column[j * 4];
 | |
|    }
 | |
|    memcpy(m, &tmp, sizeof tmp);
 | |
| }
 | |
| 
 | |
| /** 
 | |
|  * Rotates a 4x4 matrix.
 | |
|  *
 | |
|  * @param[in,out] m the matrix to rotate
 | |
|  * @param angle the angle to rotate
 | |
|  * @param x the x component of the direction to rotate to
 | |
|  * @param y the y component of the direction to rotate to
 | |
|  * @param z the z component of the direction to rotate to
 | |
|  */
 | |
| static void
 | |
| rotate(GLfloat *m, GLfloat angle, GLfloat x, GLfloat y, GLfloat z)
 | |
| {
 | |
|    double s = sin (angle);
 | |
|    double c = cos (angle);
 | |
| 
 | |
|    GLfloat r[16] = {
 | |
|       x * x * (1 - c) + c,     y * x * (1 - c) + z * s, x * z * (1 - c) - y * s, 0,
 | |
|       x * y * (1 - c) - z * s, y * y * (1 - c) + c,     y * z * (1 - c) + x * s, 0,
 | |
|       x * z * (1 - c) + y * s, y * z * (1 - c) - x * s, z * z * (1 - c) + c,     0,
 | |
|       0, 0, 0, 1
 | |
|    };
 | |
| 
 | |
|    multiply(m, r);
 | |
| }
 | |
| 
 | |
| /** 
 | |
|  * Translates a 4x4 matrix.
 | |
|  * 
 | |
|  * @param[in,out] m the matrix to translate
 | |
|  * @param x the x component of the direction to translate to
 | |
|  * @param y the y component of the direction to translate to
 | |
|  * @param z the z component of the direction to translate to
 | |
|  */
 | |
| static void
 | |
| translate(GLfloat *m, GLfloat x, GLfloat y, GLfloat z)
 | |
| {
 | |
|    GLfloat t[16] = { 1, 0, 0, 0,  0, 1, 0, 0,  0, 0, 1, 0,  x, y, z, 1 };
 | |
| 
 | |
|    multiply(m, t);
 | |
| }
 | |
| 
 | |
| /** 
 | |
|  * Creates an identity 4x4 matrix.
 | |
|  * 
 | |
|  * @param m the matrix make an identity matrix
 | |
|  */
 | |
| static void
 | |
| identity(GLfloat *m)
 | |
| {
 | |
|    GLfloat t[16] = {
 | |
|       1.0, 0.0, 0.0, 0.0,
 | |
|       0.0, 1.0, 0.0, 0.0,
 | |
|       0.0, 0.0, 1.0, 0.0,
 | |
|       0.0, 0.0, 0.0, 1.0,
 | |
|    };
 | |
| 
 | |
|    memcpy(m, t, sizeof(t));
 | |
| }
 | |
| 
 | |
| /** 
 | |
|  * Transposes a 4x4 matrix.
 | |
|  *
 | |
|  * @param m the matrix to transpose
 | |
|  */
 | |
| static void
 | |
| transpose(GLfloat *m)
 | |
| {
 | |
|    GLfloat t[16] = {
 | |
|       m[0], m[4], m[8],  m[12],
 | |
|       m[1], m[5], m[9],  m[13],
 | |
|       m[2], m[6], m[10], m[14],
 | |
|       m[3], m[7], m[11], m[15]};
 | |
| 
 | |
|    memcpy(m, t, sizeof(t));
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Inverts a 4x4 matrix.
 | |
|  *
 | |
|  * This function can currently handle only pure translation-rotation matrices.
 | |
|  * Read http://www.gamedev.net/community/forums/topic.asp?topic_id=425118
 | |
|  * for an explanation.
 | |
|  */
 | |
| static void
 | |
| invert(GLfloat *m)
 | |
| {
 | |
|    GLfloat t[16];
 | |
|    identity(t);
 | |
| 
 | |
|    // Extract and invert the translation part 't'. The inverse of a
 | |
|    // translation matrix can be calculated by negating the translation
 | |
|    // coordinates.
 | |
|    t[12] = -m[12]; t[13] = -m[13]; t[14] = -m[14];
 | |
| 
 | |
|    // Invert the rotation part 'r'. The inverse of a rotation matrix is
 | |
|    // equal to its transpose.
 | |
|    m[12] = m[13] = m[14] = 0;
 | |
|    transpose(m);
 | |
| 
 | |
|    // inv(m) = inv(r) * inv(t)
 | |
|    multiply(m, t);
 | |
| }
 | |
| 
 | |
| /** 
 | |
|  * Calculate a perspective projection transformation.
 | |
|  * 
 | |
|  * @param m the matrix to save the transformation in
 | |
|  * @param fovy the field of view in the y direction
 | |
|  * @param aspect the view aspect ratio
 | |
|  * @param zNear the near clipping plane
 | |
|  * @param zFar the far clipping plane
 | |
|  */
 | |
| void perspective(GLfloat *m, GLfloat fovy, GLfloat aspect, GLfloat zNear, GLfloat zFar)
 | |
| {
 | |
|    GLfloat tmp[16];
 | |
|    double sine, cosine, cotangent, deltaZ;
 | |
|    GLfloat radians = fovy / 2 * M_PI / 180;
 | |
|    identity(tmp);
 | |
| 
 | |
|    deltaZ = zFar - zNear;
 | |
|    sincos(radians, &sine, &cosine);
 | |
| 
 | |
|    if ((deltaZ == 0) || (sine == 0) || (aspect == 0))
 | |
|       return;
 | |
| 
 | |
|    cotangent = cosine / sine;
 | |
| 
 | |
|    tmp[0] = cotangent / aspect;
 | |
|    tmp[5] = cotangent;
 | |
|    tmp[10] = -(zFar + zNear) / deltaZ;
 | |
|    tmp[11] = -1;
 | |
|    tmp[14] = -2 * zNear * zFar / deltaZ;
 | |
|    tmp[15] = 0;
 | |
| 
 | |
|    memcpy(m, tmp, sizeof(tmp));
 | |
| }
 | |
| 
 | |
| /**
 | |
|  * Draws a gear.
 | |
|  *
 | |
|  * @param gear the gear to draw
 | |
|  * @param transform the current transformation matrix
 | |
|  * @param x the x position to draw the gear at
 | |
|  * @param y the y position to draw the gear at
 | |
|  * @param angle the rotation angle of the gear
 | |
|  * @param color the color of the gear
 | |
|  */
 | |
| static void
 | |
| draw_gear(GtkGears *self,
 | |
|           struct gear *gear,
 | |
|           GLuint gear_vbo,
 | |
|           GLfloat *transform,
 | |
|           GLfloat x,
 | |
|           GLfloat y,
 | |
|           GLfloat angle,
 | |
|           const GLfloat color[4])
 | |
| {
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (self);
 | |
|   GLfloat model_view[16];
 | |
|   GLfloat normal_matrix[16];
 | |
|   GLfloat model_view_projection[16];
 | |
|   int n;
 | |
| 
 | |
|   /* Translate and rotate the gear */
 | |
|   memcpy(model_view, transform, sizeof (model_view));
 | |
|   translate(model_view, x, y, 0);
 | |
|   rotate(model_view, 2 * G_PI * angle / 360.0, 0, 0, 1);
 | |
| 
 | |
|   /* Create and set the ModelViewProjectionMatrix */
 | |
|   memcpy(model_view_projection, priv->ProjectionMatrix, sizeof(model_view_projection));
 | |
|   multiply(model_view_projection, model_view);
 | |
| 
 | |
|   glUniformMatrix4fv(priv->ModelViewProjectionMatrix_location, 1, GL_FALSE,
 | |
|                      model_view_projection);
 | |
| 
 | |
|   /* 
 | |
|    * Create and set the NormalMatrix. It's the inverse transpose of the
 | |
|    * ModelView matrix.
 | |
|    */
 | |
|   memcpy(normal_matrix, model_view, sizeof (normal_matrix));
 | |
|   invert(normal_matrix);
 | |
|   transpose(normal_matrix);
 | |
|   glUniformMatrix4fv(priv->NormalMatrix_location, 1, GL_FALSE, normal_matrix);
 | |
| 
 | |
|   /* Set the gear color */
 | |
|   glUniform4fv(priv->MaterialColor_location, 1, color);
 | |
| 
 | |
|   /* Set the vertex buffer object to use */
 | |
|   glBindBuffer(GL_ARRAY_BUFFER, gear_vbo);
 | |
| 
 | |
|   /* Set up the position of the attributes in the vertex buffer object */
 | |
|   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), NULL);
 | |
|   glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLfloat *) 0 + 3);
 | |
| 
 | |
|   /* Enable the attributes */
 | |
|   glEnableVertexAttribArray(0);
 | |
|   glEnableVertexAttribArray(1);
 | |
| 
 | |
|   /* Draw the triangle strips that comprise the gear */
 | |
|   for (n = 0; n < gear->nstrips; n++) {
 | |
|     glDrawArrays(GL_TRIANGLE_STRIP, gear->strips[n].first, gear->strips[n].count);
 | |
|   }
 | |
| 
 | |
|   /* Disable the attributes */
 | |
|   glDisableVertexAttribArray(1);
 | |
|   glDisableVertexAttribArray(0);
 | |
| }
 | |
| 
 | |
| /* new window size or exposure */
 | |
| static void
 | |
| gtk_gears_reshape (GtkGLArea *area, int width, int height)
 | |
| {
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private ((GtkGears *) area);
 | |
| 
 | |
|   /* Update the projection matrix */
 | |
|   perspective (priv->ProjectionMatrix, 60.0, width / (float)height, 1.0, 1024.0);
 | |
| 
 | |
|   /* Set the viewport */
 | |
|   glViewport (0, 0, (GLint) width, (GLint) height);
 | |
| }
 | |
| 
 | |
| static gboolean
 | |
| gtk_gears_render (GtkGLArea    *area,
 | |
|                   GdkGLContext *context)
 | |
| {
 | |
|   static const GLfloat red[4]   = { 0.8, 0.1, 0.0, 1.0 };
 | |
|   static const GLfloat green[4] = { 0.0, 0.8, 0.2, 1.0 };
 | |
|   static const GLfloat blue[4]  = { 0.2, 0.2, 1.0, 1.0 };
 | |
| 
 | |
|   GtkGears *self = GTK_GEARS (area);
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (self);
 | |
|   GLfloat transform[16];
 | |
| 
 | |
|   identity (transform);
 | |
| 
 | |
|   glClearColor (0.0, 0.0, 0.0, 0.0);
 | |
|   glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 | |
| 
 | |
|   /* Translate and rotate the view */
 | |
|   translate (transform, 0, 0, -20);
 | |
|   rotate (transform, 2 * G_PI * priv->view_rot[0] / 360.0, 1, 0, 0);
 | |
|   rotate (transform, 2 * G_PI * priv->view_rot[1] / 360.0, 0, 1, 0);
 | |
|   rotate (transform, 2 * G_PI * priv->view_rot[2] / 360.0, 0, 0, 1);
 | |
| 
 | |
|   /* Draw the gears */
 | |
|   draw_gear (self, priv->gear1, priv->gear_vbo[0], transform, -3.0, -2.0,      priv->angle,        red);
 | |
|   draw_gear (self, priv->gear2, priv->gear_vbo[1], transform,  3.1, -2.0, -2 * priv->angle - 9.0,  green);
 | |
|   draw_gear (self, priv->gear3, priv->gear_vbo[2], transform, -3.1,  4.2, -2 * priv->angle - 25.0, blue);
 | |
| 
 | |
|   return TRUE;
 | |
| }
 | |
| 
 | |
| static const char vertex_shader_gl[] =
 | |
| "#version 330\n"
 | |
| "\n"
 | |
| "in vec3 position;\n"
 | |
| "in vec3 normal;\n"
 | |
| "\n"
 | |
| "uniform mat4 ModelViewProjectionMatrix;\n"
 | |
| "uniform mat4 NormalMatrix;\n"
 | |
| "uniform vec4 LightSourcePosition;\n"
 | |
| "uniform vec4 MaterialColor;\n"
 | |
| "\n"
 | |
| "smooth out vec4 Color;\n"
 | |
| "\n"
 | |
| "void main(void)\n"
 | |
| "{\n"
 | |
| "    // Transform the normal to eye coordinates\n"
 | |
| "    vec3 N = normalize(vec3(NormalMatrix * vec4(normal, 1.0)));\n"
 | |
| "\n"
 | |
| "    // The LightSourcePosition is actually its direction for directional light\n"
 | |
| "    vec3 L = normalize(LightSourcePosition.xyz);\n"
 | |
| "\n"
 | |
| "    // Multiply the diffuse value by the vertex color (which is fixed in this case)\n"
 | |
| "    // to get the actual color that we will use to draw this vertex with\n"
 | |
| "    float diffuse = max(dot(N, L), 0.0);\n"
 | |
| "    Color = diffuse * MaterialColor;\n"
 | |
| "\n"
 | |
| "    // Transform the position to clip coordinates\n"
 | |
| "    gl_Position = ModelViewProjectionMatrix * vec4(position, 1.0);\n"
 | |
| "}";
 | |
| 
 | |
| static const char fragment_shader_gl[] =
 | |
| "#version 330\n"
 | |
| "\n"
 | |
| "smooth in vec4 Color;\n"
 | |
| "\n"
 | |
| "out vec4 vertexColor;\n"
 | |
| "\n"
 | |
| "void main(void)\n"
 | |
| "{\n"
 | |
| "    vertexColor = Color;\n"
 | |
| "}";
 | |
| 
 | |
| static const char vertex_shader_gles[] =
 | |
| "attribute vec3 position;\n"
 | |
| "attribute vec3 normal;\n"
 | |
| "\n"
 | |
| "uniform mat4 ModelViewProjectionMatrix;\n"
 | |
| "uniform mat4 NormalMatrix;\n"
 | |
| "uniform vec4 LightSourcePosition;\n"
 | |
| "uniform vec4 MaterialColor;\n"
 | |
| "\n"
 | |
| "varying vec4 Color;\n"
 | |
| "\n"
 | |
| "void main(void)\n"
 | |
| "{\n"
 | |
| "    // Transform the normal to eye coordinates\n"
 | |
| "    vec3 N = normalize(vec3(NormalMatrix * vec4(normal, 1.0)));\n"
 | |
| "\n"
 | |
| "    // The LightSourcePosition is actually its direction for directional light\n"
 | |
| "    vec3 L = normalize(LightSourcePosition.xyz);\n"
 | |
| "\n"
 | |
| "    // Multiply the diffuse value by the vertex color (which is fixed in this case)\n"
 | |
| "    // to get the actual color that we will use to draw this vertex with\n"
 | |
| "    float diffuse = max(dot(N, L), 0.0);\n"
 | |
| "    Color = diffuse * MaterialColor;\n"
 | |
| "\n"
 | |
| "    // Transform the position to clip coordinates\n"
 | |
| "    gl_Position = ModelViewProjectionMatrix * vec4(position, 1.0);\n"
 | |
| "}";
 | |
| 
 | |
| static const char fragment_shader_gles[] =
 | |
| "precision mediump float;\n"
 | |
| "varying vec4 Color;\n"
 | |
| "\n"
 | |
| "void main(void)\n"
 | |
| "{\n"
 | |
| "    gl_FragColor = Color;\n"
 | |
| "}";
 | |
| 
 | |
| static void
 | |
| gtk_gears_realize (GtkWidget *widget)
 | |
| {
 | |
|   GtkGLArea *glarea = GTK_GL_AREA (widget);
 | |
|   GtkGears *gears = GTK_GEARS (widget);
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
|   GdkGLContext *context;
 | |
|   GLuint vao, v, f, program;
 | |
|   const char *p;
 | |
|   char msg[512];
 | |
| 
 | |
|   GTK_WIDGET_CLASS (gtk_gears_parent_class)->realize (widget);
 | |
| 
 | |
|   gtk_gl_area_make_current (glarea);
 | |
|   if (gtk_gl_area_get_error (glarea) != NULL)
 | |
|     return;
 | |
| 
 | |
|   context = gtk_gl_area_get_context (glarea);
 | |
| 
 | |
|   glEnable (GL_CULL_FACE);
 | |
|   glEnable (GL_DEPTH_TEST);
 | |
| 
 | |
|   /* Create the VAO */
 | |
|   glGenVertexArrays (1, &vao);
 | |
|   glBindVertexArray (vao);
 | |
|   priv->vao = vao;
 | |
| 
 | |
|   /* Compile the vertex shader */
 | |
|   if (gdk_gl_context_get_use_es (context))
 | |
|     p = vertex_shader_gles;
 | |
|   else
 | |
|     p = vertex_shader_gl;
 | |
|   v = glCreateShader(GL_VERTEX_SHADER);
 | |
|   glShaderSource(v, 1, &p, NULL);
 | |
|   glCompileShader(v);
 | |
|   glGetShaderInfoLog(v, sizeof msg, NULL, msg);
 | |
|   g_print ("vertex shader info: %s\n", msg);
 | |
| 
 | |
|   /* Compile the fragment shader */
 | |
|   if (gdk_gl_context_get_use_es (context))
 | |
|     p = fragment_shader_gles;
 | |
|   else
 | |
|     p = fragment_shader_gl;
 | |
|   f = glCreateShader(GL_FRAGMENT_SHADER);
 | |
|   glShaderSource(f, 1, &p, NULL);
 | |
|   glCompileShader(f);
 | |
|   glGetShaderInfoLog(f, sizeof msg, NULL, msg);
 | |
|   g_print ("fragment shader info: %s\n", msg);
 | |
| 
 | |
|   /* Create and link the shader program */
 | |
|   program = glCreateProgram();
 | |
|   glAttachShader(program, v);
 | |
|   glAttachShader(program, f);
 | |
|   glBindAttribLocation(program, 0, "position");
 | |
|   glBindAttribLocation(program, 1, "normal");
 | |
| 
 | |
|   glLinkProgram(program);
 | |
|   glGetProgramInfoLog(program, sizeof msg, NULL, msg);
 | |
|   g_print ("program info: %s\n", msg);
 | |
|   glDeleteShader (v);
 | |
|   glDeleteShader (f);
 | |
| 
 | |
|   /* Enable the shaders */
 | |
|   glUseProgram(program);
 | |
|   priv->program = program;
 | |
| 
 | |
|   /* Get the locations of the uniforms so we can access them */
 | |
|   priv->ModelViewProjectionMatrix_location = glGetUniformLocation(program, "ModelViewProjectionMatrix");
 | |
|   priv->NormalMatrix_location = glGetUniformLocation(program, "NormalMatrix");
 | |
|   priv->LightSourcePosition_location = glGetUniformLocation(program, "LightSourcePosition");
 | |
|   priv->MaterialColor_location = glGetUniformLocation(program, "MaterialColor");
 | |
| 
 | |
|   /* Set the LightSourcePosition uniform which is constant throught the program */
 | |
|   glUniform4fv(priv->LightSourcePosition_location, 1, priv->LightSourcePosition);
 | |
| 
 | |
|   /* make the gears */
 | |
|   priv->gear1 = create_gear(1.0, 4.0, 1.0, 20, 0.7);
 | |
| 
 | |
|   /* Store the vertices in a vertex buffer object (VBO) */
 | |
|   glGenBuffers (1, &(priv->gear_vbo[0]));
 | |
|   glBindBuffer (GL_ARRAY_BUFFER, priv->gear_vbo[0]);
 | |
|   glBufferData (GL_ARRAY_BUFFER,
 | |
|                 priv->gear1->nvertices * sizeof(GearVertex),
 | |
|                 priv->gear1->vertices,
 | |
|                 GL_STATIC_DRAW);
 | |
| 
 | |
|   priv->gear2 = create_gear(0.5, 2.0, 2.0, 10, 0.7);
 | |
|   glGenBuffers (1, &(priv->gear_vbo[1]));
 | |
|   glBindBuffer (GL_ARRAY_BUFFER, priv->gear_vbo[1]);
 | |
|   glBufferData (GL_ARRAY_BUFFER,
 | |
|                 priv->gear2->nvertices * sizeof(GearVertex),
 | |
|                 priv->gear2->vertices,
 | |
|                 GL_STATIC_DRAW);
 | |
| 
 | |
|   priv->gear3 = create_gear(1.3, 2.0, 0.5, 10, 0.7);
 | |
|   glGenBuffers (1, &(priv->gear_vbo[2]));
 | |
|   glBindBuffer (GL_ARRAY_BUFFER, priv->gear_vbo[2]);
 | |
|   glBufferData (GL_ARRAY_BUFFER,
 | |
|                 priv->gear3->nvertices * sizeof(GearVertex),
 | |
|                 priv->gear3->vertices,
 | |
|                 GL_STATIC_DRAW);
 | |
| }
 | |
| 
 | |
| static void
 | |
| gtk_gears_unrealize (GtkWidget *widget)
 | |
| {
 | |
|   GtkGLArea *glarea = GTK_GL_AREA (widget);
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private ((GtkGears *) widget);
 | |
| 
 | |
|   gtk_gl_area_make_current (glarea);
 | |
|   if (gtk_gl_area_get_error (glarea) != NULL)
 | |
|     return;
 | |
| 
 | |
|   /* Release the resources associated with OpenGL */
 | |
|   if (priv->gear_vbo[0] != 0)
 | |
|     glDeleteBuffers (1, &(priv->gear_vbo[0]));
 | |
| 
 | |
|   if (priv->gear_vbo[1] != 0)
 | |
|     glDeleteBuffers (1, &(priv->gear_vbo[1]));
 | |
| 
 | |
|   if (priv->gear_vbo[2] != 0)
 | |
|     glDeleteBuffers (1, &(priv->gear_vbo[2]));
 | |
| 
 | |
|   if (priv->vao != 0)
 | |
|     glDeleteVertexArrays (1, &priv->vao);
 | |
| 
 | |
|   if (priv->program != 0)
 | |
|     glDeleteProgram (priv->program);
 | |
| 
 | |
|   priv->ModelViewProjectionMatrix_location = 0;
 | |
|   priv->NormalMatrix_location = 0;
 | |
|   priv->LightSourcePosition_location = 0;
 | |
|   priv->MaterialColor_location = 0;
 | |
| 
 | |
|   GTK_WIDGET_CLASS (gtk_gears_parent_class)->unrealize (widget);
 | |
| }
 | |
| 
 | |
| static gboolean
 | |
| gtk_gears_tick (GtkWidget     *widget,
 | |
|                 GdkFrameClock *frame_clock,
 | |
|                 gpointer       user_data)
 | |
| {
 | |
|   GtkGears *gears = GTK_GEARS (widget);
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
|   GdkFrameTimings *timings, *previous_timings;
 | |
|   gint64 previous_frame_time = 0;
 | |
|   gint64 frame_time;
 | |
|   gint64 history_start, history_len;
 | |
|   gint64 frame;
 | |
|   char *s;
 | |
| 
 | |
|   frame = gdk_frame_clock_get_frame_counter (frame_clock);
 | |
|   frame_time = gdk_frame_clock_get_frame_time (frame_clock);
 | |
| 
 | |
|   if (priv->first_frame_time == 0)
 | |
|     {
 | |
|       /* No need for changes on first frame */
 | |
|       priv->first_frame_time = frame_time;
 | |
|       if (priv->fps_label)
 | |
|         gtk_label_set_label (priv->fps_label, "FPS: ---");
 | |
|       return G_SOURCE_CONTINUE;
 | |
|     }
 | |
| 
 | |
|   /* glxgears advances 70 degrees per second, so do the same */
 | |
| 
 | |
|   priv->angle = fmod ((frame_time - priv->first_frame_time) / (double)G_USEC_PER_SEC * 70.0, 360.0);
 | |
| 
 | |
|   gtk_widget_queue_draw (widget);
 | |
| 
 | |
|   history_start = gdk_frame_clock_get_history_start (frame_clock);
 | |
| 
 | |
|   if (priv->fps_label && frame % 60 == 0)
 | |
|     {
 | |
|       history_len = frame - history_start;
 | |
|       if (history_len > 0)
 | |
|         {
 | |
|           previous_timings = gdk_frame_clock_get_timings (frame_clock, frame - history_len);
 | |
|           previous_frame_time = gdk_frame_timings_get_frame_time (previous_timings);
 | |
| 
 | |
|           s = g_strdup_printf ("FPS: %-4.1f", (G_USEC_PER_SEC * history_len) / (double)(frame_time - previous_frame_time));
 | |
|           gtk_label_set_label (priv->fps_label, s);
 | |
|           g_free (s);
 | |
|         }
 | |
|     }
 | |
| 
 | |
|   timings = gdk_frame_clock_get_current_timings (frame_clock);
 | |
|   previous_timings = gdk_frame_clock_get_timings (frame_clock,
 | |
|                                                   gdk_frame_timings_get_frame_counter (timings) - 1);
 | |
|   if (previous_timings != NULL)
 | |
|     previous_frame_time = gdk_frame_timings_get_frame_time (previous_timings);
 | |
| 
 | |
|   return G_SOURCE_CONTINUE;
 | |
| }
 | |
| 
 | |
| void
 | |
| gtk_gears_set_axis (GtkGears *gears, int axis, double value)
 | |
| {
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
| 
 | |
|   if (axis < 0 || axis >= GTK_GEARS_N_AXIS)
 | |
|     return;
 | |
| 
 | |
|   priv->view_rot[axis] = value;
 | |
| 
 | |
|   gtk_widget_queue_draw (GTK_WIDGET (gears));
 | |
| }
 | |
| 
 | |
| double
 | |
| gtk_gears_get_axis (GtkGears *gears, int axis)
 | |
| {
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
| 
 | |
|   if (axis < 0 || axis >= GTK_GEARS_N_AXIS)
 | |
|     return 0.0;
 | |
| 
 | |
|   return priv->view_rot[axis];
 | |
| }
 | |
| 
 | |
| void
 | |
| gtk_gears_set_fps_label (GtkGears *gears, GtkLabel *label)
 | |
| {
 | |
|   GtkGearsPrivate *priv = gtk_gears_get_instance_private (gears);
 | |
| 
 | |
|   if (label)
 | |
|     g_object_ref (label);
 | |
| 
 | |
|   g_clear_object (&priv->fps_label);
 | |
| 
 | |
|   priv->fps_label = label;
 | |
| }
 |