--- /dev/null
+/*
+ * Test glTexSubImage mid-way through a frame.
+ *
+ * The same texture is used for both quads but it gets redefined
+ * with glTexSubImage (or glTexImage) after the first quad.
+ */
+
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "GL/glut.h"
+
+static GLuint Window = 0;
+static GLboolean Anim = GL_FALSE;
+static GLfloat Angle = 0.0f;
+
+
+
+static void
+first_texture(void)
+{
+ static int width=8, height=8;
+ static GLubyte tex1[] = {
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 0, 1, 0, 0, 0,
+ 0, 0, 0, 1, 1, 0, 0, 0,
+ 0, 0, 0, 0, 1, 0, 0, 0,
+ 0, 0, 0, 0, 1, 0, 0, 0,
+ 0, 0, 0, 0, 1, 0, 0, 0,
+ 0, 0, 0, 1, 1, 1, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0 };
+
+ GLubyte tex[64][3];
+ GLint i, j;
+
+ /* red on white */
+ for (i=0;i<height;i++) {
+ for (j=0;j<width;j++) {
+ int p = i*width+j;
+ if (tex1[(height-i-1)*width+j]) {
+ tex[p][0] = 255; tex[p][1] = 0; tex[p][2] = 0;
+ }
+ else {
+ tex[p][0] = 255; tex[p][1] = 255; tex[p][2] = 255;
+ }
+ }
+ }
+
+ glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
+ GL_RGB, GL_UNSIGNED_BYTE, tex );
+}
+
+
+static void
+second_texture(void)
+{
+ static int width=8, height=8;
+
+ static GLubyte tex2[] = {
+ 0, 0, 0, 0, 0, 0, 0, 0,
+ 0, 0, 0, 2, 2, 0, 0, 0,
+ 0, 0, 2, 0, 0, 2, 0, 0,
+ 0, 0, 0, 0, 0, 2, 0, 0,
+ 0, 0, 0, 0, 2, 0, 0, 0,
+ 0, 0, 0, 2, 0, 0, 0, 0,
+ 0, 0, 2, 2, 2, 2, 0, 0,
+ 0, 0, 0, 0, 0, 0, 0, 0 };
+
+ GLubyte tex[64][3];
+ GLint i, j;
+
+ /* green on blue */
+ for (i=0;i<height;i++) {
+ for (j=0;j<width;j++) {
+ int p = i*width+j;
+ if (tex2[(height-i-1)*width+j]) {
+ tex[p][0] = 0; tex[p][1] = 255; tex[p][2] = 0;
+ }
+ else {
+ tex[p][0] = 0; tex[p][1] = 0; tex[p][2] = 255;
+ }
+ }
+ }
+#if 0
+ glTexImage2D( GL_TEXTURE_2D, 0, 3, width, height, 0,
+ GL_RGB, GL_UNSIGNED_BYTE, tex );
+#else
+ glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, width, height,
+ GL_RGB, GL_UNSIGNED_BYTE, tex );
+#endif
+}
+
+
+
+static void draw( void )
+{
+ glClear( GL_COLOR_BUFFER_BIT );
+
+ glColor3f( 1.0, 1.0, 1.0 );
+
+ /* draw first polygon */
+ glPushMatrix();
+ glTranslatef( -1.0, 0.0, 0.0 );
+ glRotatef( Angle, 0.0, 0.0, 1.0 );
+
+ first_texture();
+
+ glBegin( GL_POLYGON );
+ glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );
+ glTexCoord2f( 1.0, 0.0 ); glVertex2f( 1.0, -1.0 );
+ glTexCoord2f( 1.0, 1.0 ); glVertex2f( 1.0, 1.0 );
+ glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0, 1.0 );
+ glEnd();
+ glPopMatrix();
+
+ /* draw second polygon */
+ glPushMatrix();
+ glTranslatef( 1.0, 0.0, 0.0 );
+ glRotatef( Angle-90.0, 0.0, 1.0, 0.0 );
+
+ second_texture();
+
+ glBegin( GL_POLYGON );
+ glTexCoord2f( 0.0, 0.0 ); glVertex2f( -1.0, -1.0 );
+ glTexCoord2f( 1.0, 0.0 ); glVertex2f( 1.0, -1.0 );
+ glTexCoord2f( 1.0, 1.0 ); glVertex2f( 1.0, 1.0 );
+ glTexCoord2f( 0.0, 1.0 ); glVertex2f( -1.0, 1.0 );
+ glEnd();
+ glPopMatrix();
+
+ glutSwapBuffers();
+}
+
+
+
+static void idle( void )
+{
+ static double t0 = -1.;
+ double dt, t = glutGet(GLUT_ELAPSED_TIME) / 1000.0;
+ if (t0 < 0.0)
+ t0 = t;
+ dt = t - t0;
+ t0 = t;
+ Angle += 120.0*dt;
+ glutPostRedisplay();
+}
+
+
+
+/* change view Angle, exit upon ESC */
+static void key(unsigned char k, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (k) {
+ case 'a':
+ Anim = !Anim;
+ if (Anim)
+ glutIdleFunc( idle );
+ else
+ glutIdleFunc( NULL );
+ break;
+ case 27:
+ glutDestroyWindow(Window);
+ exit(0);
+ }
+}
+
+
+
+/* new window size or exposure */
+static void reshape( int width, int height )
+{
+ glViewport(0, 0, (GLint)width, (GLint)height);
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ /* glOrtho( -3.0, 3.0, -3.0, 3.0, -10.0, 10.0 );*/
+ glFrustum( -2.0, 2.0, -2.0, 2.0, 6.0, 20.0 );
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+ glTranslatef( 0.0, 0.0, -8.0 );
+}
+
+
+static void init( void )
+{
+ /* Setup texturing */
+ glEnable( GL_TEXTURE_2D );
+ glTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL );
+
+
+ glBindTexture( GL_TEXTURE_2D, 0 );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
+ glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT );
+}
+
+
+
+int main( int argc, char *argv[] )
+{
+ glutInit(&argc, argv);
+ glutInitWindowPosition(0, 0);
+ glutInitWindowSize(300, 300);
+ glutInitDisplayMode( GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE );
+
+ Window = glutCreateWindow("Texture Objects");
+ if (!Window) {
+ exit(1);
+ }
+
+ init();
+
+ glutReshapeFunc( reshape );
+ glutKeyboardFunc( key );
+ if (Anim)
+ glutIdleFunc( idle );
+ glutDisplayFunc( draw );
+ glutMainLoop();
+ return 0;
+}