--- /dev/null
+/*
+ * 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;
+}
{
if (sampler->state->min_mip_filter == PIPE_TEX_MIPFILTER_NONE) {
/* no mipmap selection needed */
- *imgFilter = sampler->state->mag_img_filter;
- *level0 = *level1 = (int) sampler->state->min_lod;
+ *level0 = *level1 = CLAMP((int) sampler->state->min_lod,
+ 0, (int) sampler->texture->last_level);
+
+ if (sampler->state->min_img_filter != sampler->state->mag_img_filter) {
+ /* non-mipmapped texture, but still need to determine if doing
+ * minification or magnification.
+ */
+ float lambda = compute_lambda(sampler, s, t, p, lodbias);
+ if (lambda <= 0.0) {
+ *imgFilter = sampler->state->mag_img_filter;
+ }
+ else {
+ *imgFilter = sampler->state->min_img_filter;
+ }
+ }
+ else {
+ *imgFilter = sampler->state->mag_img_filter;
+ }
}
else {
float lambda;
/* vertex shader */
lambda = lodbias; /* not really a bias, but absolute LOD */
- if (lambda < 0.0) { /* XXX threshold depends on the filter */
+ if (lambda <= 0.0) { /* XXX threshold depends on the filter */
/* magnifying */
*imgFilter = sampler->state->mag_img_filter;
*level0 = *level1 = 0;
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