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Learning_GTK4_tree/demos/gtk-demo/gtkgears.c

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2023-12-12 11:36:42 +01:00
/* 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
static inline void
_sincos (double x, double *_sin, double *_cos)
{
#ifdef HAVE_SINCOS
sincos (x, _sin, _cos);
#else
*_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 coordinate
* @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->vertices);
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 various 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 150\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 150\n"
"\n"
"smooth in vec4 Color;\n"
"\n"
"void main(void)\n"
"{\n"
" gl_FragColor = 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);
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;
glEnable (GL_CULL_FACE);
glEnable (GL_DEPTH_TEST);
/* Create the VAO */
glGenVertexArrays (1, &vao);
glBindVertexArray (vao);
priv->vao = vao;
/* Compile the vertex shader */
if (gtk_gl_area_get_api (glarea) == GDK_GL_API_GLES)
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_debug ("vertex shader info: %s\n", msg);
/* Compile the fragment shader */
if (gtk_gl_area_get_api (glarea) == GDK_GL_API_GLES)
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_debug ("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_debug ("program info: %s\n", msg);
glDetachShader (program, v);
glDetachShader (program, f);
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 throughout 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)
{
/* 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 *previous_timings;
gint64 previous_frame_time;
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);
}
}
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;
}