1 files changed, 223 insertions, 0 deletions
diff --git a/progs/tests/zcomp.c b/progs/tests/zcomp.c
new file mode 100644
index 0000000000..b53079d07f
--- /dev/null
+++ b/progs/tests/zcomp.c
@@ -0,0 +1,223 @@
+/**
+ * Test Z compositing with glDrawPixels(GL_DEPTH_COMPONENT) and stencil test.
+ */
+
+#define GL_GLEXT_PROTOTYPES
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glut.h>
+#include "../util/showbuffer.c"
+
+
+static int Win;
+static GLfloat Xrot = 0, Yrot = 0, Zpos = 6;
+static GLboolean Anim = GL_FALSE;
+
+static int Width = 400, Height = 200;
+static GLfloat *Zimg;
+static GLubyte *Cimg;
+static GLboolean showZ = 0;
+
+
+static void
+Idle(void)
+{
+   Xrot += 3.0;
+   Yrot += 4.0;
+   glutPostRedisplay();
+}
+
+
+/**
+ * Draw first object, save color+Z images
+ */
+static void
+DrawFirst(void)
+{
+   static const GLfloat red[4] = { 1.0, 0.0, 0.0, 0.0 };
+
+   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, red);
+
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+   glPushMatrix();
+   glTranslatef(-1, 0, 0);
+   glRotatef(45 + Xrot, 1, 0, 0);
+
+   glutSolidTorus(0.75, 2.0, 10, 20);
+
+   glPopMatrix();
+
+   glReadPixels(0, 0, Width, Height, GL_DEPTH_COMPONENT, GL_FLOAT, Zimg);
+   glReadPixels(0, 0, Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, Cimg);
+}
+
+
+/**
+ * Draw second object.
+ */
+static void
+DrawSecond(void)
+{
+   static const GLfloat blue[4] = { 0.0, 0.0, 1.0, 0.0 };
+
+   glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, blue);
+
+   glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
+
+   glPushMatrix();
+   glTranslatef(+1, 0, 0);
+   glRotatef(-45 + Xrot, 1, 0, 0);
+
+   glutSolidTorus(0.75, 2.0, 10, 20);
+
+   glPopMatrix();
+}
+
+
+/**
+ * Composite first/saved image over second rendering.
+ */
+static void
+Composite(void)
+{
+   glWindowPos2i(0, 0);
+
+   /* Draw Z values, set stencil where Z test passes */
+   glEnable(GL_STENCIL_TEST);
+   glStencilFunc(GL_ALWAYS, 1, ~0);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
+   glColorMask(0,0,0,0);
+   glDrawPixels(Width, Height, GL_DEPTH_COMPONENT, GL_FLOAT, Zimg);
+   glColorMask(1,1,1,1);
+
+   /* Draw color where stencil==1 */
+   glStencilFunc(GL_EQUAL, 1, ~0);
+   glStencilOp(GL_KEEP, GL_KEEP, GL_KEEP);
+   glDisable(GL_DEPTH_TEST);
+   glDrawPixels(Width, Height, GL_RGBA, GL_UNSIGNED_BYTE, Cimg);
+   glEnable(GL_DEPTH_TEST);
+
+   glDisable(GL_STENCIL_TEST);
+}
+
+
+static void
+Draw(void)
+{
+   DrawFirst();
+   DrawSecond();
+   Composite();
+   glutSwapBuffers();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+   GLfloat ar = (float) width / height;
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-ar, ar, -1.0, 1.0, 5.0, 30.0);
+   glMatrixMode(GL_MODELVIEW);
+   glLoadIdentity();
+   glTranslatef(0.0, 0.0, -15.0);
+
+   Width = width;
+   Height = height;
+
+   if (Zimg)
+      free(Zimg);
+   if (Cimg)
+      free(Cimg);
+   Zimg = (float *) malloc(width * height * 4);
+   Cimg = (GLubyte *) malloc(width * height * 4);
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+   const GLfloat step = 1.0;
+   (void) x;
+   (void) y;
+   switch (key) {
+      case 'a':
+         Anim = !Anim;
+         if (Anim)
+            glutIdleFunc(Idle);
+         else
+            glutIdleFunc(NULL);
+         break;
+      case 'd':
+         showZ = !showZ;
+         break;
+      case 'z':
+         Zpos -= step;
+         break;
+      case 'Z':
+         Zpos += step;
+         break;
+      case 27:
+         glutDestroyWindow(Win);
+         exit(0);
+         break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+SpecialKey(int key, int x, int y)
+{
+   const GLfloat step = 3.0;
+   (void) x;
+   (void) y;
+   switch (key) {
+      case GLUT_KEY_UP:
+         Xrot -= step;
+         break;
+      case GLUT_KEY_DOWN:
+         Xrot += step;
+         break;
+      case GLUT_KEY_LEFT:
+         Yrot -= step;
+         break;
+      case GLUT_KEY_RIGHT:
+         Yrot += step;
+         break;
+   }
+   glutPostRedisplay();
+}
+
+
+static void
+Init(void)
+{
+   /* setup lighting, etc */
+   glEnable(GL_DEPTH_TEST);
+   glEnable(GL_LIGHTING);
+   glEnable(GL_LIGHT0);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(Width, Height);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH | GLUT_STENCIL);
+   Win = glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutSpecialFunc(SpecialKey);
+   glutDisplayFunc(Draw);
+   if (Anim)
+      glutIdleFunc(Idle);
+   Init();
+   glutMainLoop();
+   return 0;
+}