--- /dev/null
+/*
+ * Exercise GL_EXT_secondary_color
+ */
+
+
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+
+static int Width = 600;
+static int Height = 200;
+static GLfloat Near = 5.0, Far = 25.0;
+
+
+static void Display( void )
+{
+ GLfloat t;
+
+ glClearColor(0.2, 0.2, 0.8, 0);
+ glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+ for (t = 0.0; t <= 1.0; t += 0.25) {
+ GLfloat x = t * 10.0 - 5.0;
+ GLfloat g = t;
+
+ /* top row: untextured */
+ glColor3f(1, 0, 0);
+ glPushMatrix();
+ glTranslatef(x, 1.2, 0);
+#if defined(GL_EXT_secondary_color)
+ glSecondaryColor3fEXT(0, g, 0);
+#endif
+ glBegin(GL_POLYGON);
+ glVertex2f(-1, -1);
+ glVertex2f( 1, -1);
+ glVertex2f( 1, 1);
+ glVertex2f(-1, 1);
+ glEnd();
+ glPopMatrix();
+
+ /* bottom row: textured */
+ glColor3f(1, 1, 1);
+ glEnable(GL_TEXTURE_2D);
+ glPushMatrix();
+ glTranslatef(x, -1.2, 0);
+#if defined(GL_EXT_secondary_color)
+ glSecondaryColor3fEXT(0, g, 0);
+#endif
+ glBegin(GL_POLYGON);
+ glTexCoord2f(0, 0); glVertex2f(-1, -1);
+ glTexCoord2f(1, 0); glVertex2f( 1, -1);
+ glTexCoord2f(1, 1); glVertex2f( 1, 1);
+ glTexCoord2f(0, 1); glVertex2f(-1, 1);
+ glEnd();
+ glPopMatrix();
+ glDisable(GL_TEXTURE_2D);
+ }
+ glutSwapBuffers();
+}
+
+
+static void Reshape( int width, int height )
+{
+ GLfloat ar = (float) width / (float) height;
+ Width = width;
+ Height = height;
+ glViewport( 0, 0, width, height );
+ glMatrixMode( GL_PROJECTION );
+ glLoadIdentity();
+ glFrustum( -ar, ar, -1.0, 1.0, Near, Far );
+ glMatrixMode( GL_MODELVIEW );
+ glLoadIdentity();
+ glTranslatef( 0.0, 0.0, -15.0 );
+}
+
+
+static void Key( unsigned char key, int x, int y )
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 27:
+ exit(0);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+static void Init( void )
+{
+ GLubyte image[4*4][3];
+ GLint i;
+ if (!glutExtensionSupported("GL_EXT_secondary_color")) {
+ printf("Sorry, this program requires GL_EXT_secondary_color\n");
+ exit(1);
+ }
+
+ /* setup red texture with one back texel */
+ for (i = 0; i < 4*4; i++) {
+ if (i == 0) {
+ image[i][0] = 0;
+ image[i][1] = 0;
+ image[i][2] = 0;
+ }
+ else {
+ image[i][0] = 255;
+ image[i][1] = 0;
+ image[i][2] = 0;
+ }
+ }
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 4, 4, 0,
+ GL_RGB, GL_UNSIGNED_BYTE, image);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+ glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+ glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
+
+#if defined(GL_EXT_secondary_color)
+ glEnable(GL_COLOR_SUM_EXT);
+#endif
+ glLightModeli(GL_LIGHT_MODEL_COLOR_CONTROL, GL_SEPARATE_SPECULAR_COLOR);
+
+ printf("Squares should be colored from red -> orange -> yellow.\n");
+ printf("Top row is untextured.\n");
+ printf("Bottom row is textured (red texture with one black texel).\n");
+ printf("Rows should be identical, except for lower-left texel.\n");
+}
+
+
+int main( int argc, char *argv[] )
+{
+ glutInit( &argc, argv );
+ glutInitWindowPosition( 0, 0 );
+ glutInitWindowSize( Width, Height );
+ glutInitDisplayMode( GLUT_RGB | GLUT_DOUBLE );
+ glutCreateWindow(argv[0]);
+ glutReshapeFunc( Reshape );
+ glutKeyboardFunc( Key );
+ glutDisplayFunc( Display );
+ Init();
+ glutMainLoop();
+ return 0;
+}