glUseProgram (0);
}
-static void
-paint_rgb_using_texture (double r, double g, double b)
+static GLuint
+create_rgb_texture (double r, double g, double b)
{
uint8_t data[3];
- GLuint texture;
+ GLuint texture = 0;
data[0] = (uint8_t) (255.0 * r);
data[1] = (uint8_t) (255.0 * g);
1, 1, 0,
GL_RGB, GL_UNSIGNED_BYTE, data);
+ return texture;
+}
+
+static void
+paint_using_texture (GLuint texture)
+{
+ glBindTexture (GL_TEXTURE_2D, texture);
+
glEnable (GL_TEXTURE_2D);
draw_fullscreen_textured_quad ();
static void
draw (Display *dpy, Window window, int width, int height)
{
+#define PASSES 2
+ int i;
GLenum glew_err;
+ GLuint texture[PASSES];
int visual_attr[] = {
GLX_RGBA,
set_2d_projection ();
- /* Frame 1: Draw a solid (magenta) frame using glClear. */
- paint_rgb_using_clear (1, 0, 1);
- glXSwapBuffers (dpy, window);
+/* Simply count through some colors, frame by frame. */
+#define RGB(frame) (((frame+1)/4) % 2), (((frame+1)/2) % 2), ((frame+1) % 2)
+
+ int frame = 0;
+ for (i = 0; i < PASSES; i++) {
+
+ /* Frame: Draw a solid frame using glClear. */
+ paint_rgb_using_clear (RGB(frame));
+ glXSwapBuffers (dpy, window);
+ frame++;
- /* Frame 2: Draw a solid (yellow) frame using GLSL. */
- paint_rgb_using_glsl (1, 1, 0);
- glXSwapBuffers (dpy, window);
+ /* Frame: Draw a solid frame using GLSL. */
+ paint_rgb_using_glsl (RGB(frame));
+ glXSwapBuffers (dpy, window);
+ frame++;
+
+ /* Frame: Draw a solid frame using a texture. */
+ texture[i] = create_rgb_texture (RGB(frame));
+ paint_using_texture (texture[i]);
+ glXSwapBuffers (dpy, window);
+ frame++;
+ }
- /* Frame 3: Draw a solid (cyan) frame using a texture. */
- paint_rgb_using_texture (0, 1, 1);
+ /* Draw another frame with a re-used texture. */
+ paint_using_texture (texture[0]);
glXSwapBuffers (dpy, window);
+ frame++;
/* Cleanup */
glXDestroyContext (dpy, ctx);