Added minmag.c test

Test that different minification and magnification filters are chosen for the
non-mipmapped texture case.

1 files changed, 198 insertions, 0 deletions

diff --git a/progs/tests/minmag.c b/progs/tests/minmag.c
new file mode 100644
index 0000000..78ef9db
--- /dev/null
+++ b/progs/tests/minmag.c
@@ -0,0 +1,198 @@
+/*
+ * Test minification vs. magnification filtering.
+ * Draw two quads with different filtering modes:
+ *
+ *    +--------------------------+  +--------------------------+
+ *    |   MagFilter = GL_LINEAR  |  |  MagFilter = GL_LINEAR   |
+ *    |   MinFilter = GL_LINEAR  |  |  MinFilter = GL_NEAREST  |
+ *    +--------------------------+  +--------------------------+
+ *
+ * They should look different when the quad is smaller than the level 0
+ * texture size (when minifying).
+ */
+
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <GL/glut.h>
+
+
+static GLint Width = 1000, Height = 500;
+
+
+static GLint TexWidth = 256, TexHeight = 256;
+static GLfloat Zpos = 5;
+static GLboolean MipMap = 0*GL_TRUE;
+static GLboolean LinearFilter = GL_TRUE;
+
+
+static void
+redraw(void)
+{
+   GLfloat w = 1.0;
+   GLfloat h = 1.0;
+
+   glClear( GL_COLOR_BUFFER_BIT );
+
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+
+   glPushMatrix();
+   glTranslatef(-1.5, 0, -Zpos);
+      glBegin(GL_POLYGON);
+      glTexCoord2f(0, 0);  glVertex2f(-w, -h);
+      glTexCoord2f(1, 0);  glVertex2f( w, -h);
+      glTexCoord2f(1, 1);  glVertex2f( w,  h);
+      glTexCoord2f(0, 1);  glVertex2f(-w,  h);
+      glEnd();
+   glPopMatrix();
+
+   glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+   glPushMatrix();
+   glTranslatef(1.5, 0, -Zpos);
+      glBegin(GL_POLYGON);
+      glTexCoord2f(0, 0);  glVertex2f(-w, -h);
+      glTexCoord2f(1, 0);  glVertex2f( w, -h);
+      glTexCoord2f(1, 1);  glVertex2f( w,  h);
+      glTexCoord2f(0, 1);  glVertex2f(-w,  h);
+      glEnd();
+   glPopMatrix();
+
+   glutSwapBuffers();
+}
+
+
+static void
+init(void)
+{
+   GLubyte color[10][4] = {
+      { 0, 0, 0, 0 },
+      { 1, 0, 0, 0 },
+      { 0, 1, 0, 0 },
+      { 0, 0, 1, 0 },
+      { 0, 1, 1, 0 },
+      { 1, 0, 1, 0 },
+      { 1, 1, 0, 0 },
+      { 1, 0, 0, 0 },
+      { 0, 1, 0, 0 },
+      { 0, 0, 1, 0 }
+   };
+   GLubyte *texImage;
+
+   printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
+   printf("Left quad should be linear filtered and right should be nearest filtered.\n");
+   printf("Press z/Z to change quad distance.\n");
+
+   texImage = (GLubyte*) malloc(4 * TexWidth * TexHeight * sizeof(GLubyte));
+   assert(texImage);
+
+   {
+      GLint level = 0;
+      GLint w = TexWidth, h = TexHeight;
+      while (1) {
+         int i, j;
+
+         for (i = 0; i < h; i++) {
+            for (j = 0;j < w; j++) {
+               if (w==1 || h==1 || (((i / 2) ^ (j / 2)) & 1)) {
+                  /*if (j < i) {*/
+                  texImage[(i*w+j) * 4 + 0] = 255;
+                  texImage[(i*w+j) * 4 + 1] = 255;
+                  texImage[(i*w+j) * 4 + 2] = 255;
+                  texImage[(i*w+j) * 4 + 3] = 255;
+               }
+               else {
+                  texImage[(i*w+j) * 4 + 0] = color[level][0] * 255;
+                  texImage[(i*w+j) * 4 + 1] = color[level][1] * 255;
+                  texImage[(i*w+j) * 4 + 2] = color[level][2] * 255;
+                  texImage[(i*w+j) * 4 + 3] = color[level][3] * 255;
+               }
+            }
+         }
+
+         glTexImage2D(GL_TEXTURE_2D, level, GL_RGBA8, w, h, 0,
+                      GL_RGBA, GL_UNSIGNED_BYTE, texImage);
+
+         printf("Texture level %d: %d x %d\n", level, w, h);
+         if (!MipMap)
+            break;
+
+         if (w == 1 && h == 1)
+            break;
+         if (w > 1)
+            w /= 2;
+         if (h > 1)
+            h /= 2;
+         level++;
+      }
+   }
+
+   free(texImage);
+
+   glClearColor(0.25, 0.25, 0.25, 1.0);
+   glEnable(GL_TEXTURE_2D);
+
+   glViewport(0, 0, Width, Height);
+}
+
+
+
+static void
+Reshape(int width, int height)
+{
+   float ar = (float) width /height;
+   Width = width;
+   Height = height;
+   glViewport(0, 0, width, height);
+   glMatrixMode(GL_PROJECTION);
+   glLoadIdentity();
+   glFrustum(-ar, ar, -1.0, 1.0, 5.0, 2500.0);
+   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 'z':
+      Zpos--;
+      break;
+   case 'Z':
+      Zpos++;
+      break;
+   case 'f':
+      LinearFilter = !LinearFilter;
+      break;
+   case 27:
+      exit(0);
+      break;
+   }
+   glutPostRedisplay();
+}
+
+
+int
+main(int argc, char *argv[])
+{
+   glutInit(&argc, argv);
+   glutInitWindowPosition(0, 0);
+   glutInitWindowSize(Width, Height);
+   glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+   glutCreateWindow(argv[0]);
+   glutReshapeFunc(Reshape);
+   glutKeyboardFunc(Key);
+   glutDisplayFunc(redraw);
+   init();
+   glutMainLoop();
+   return 0;
+}