--- /dev/null
+/*
+ * Test packed pixel formats for textures.
+ * Brian Paul
+ * 12 May 2004
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <string.h>
+#include <GL/glut.h>
+
+
+struct pixel_format {
+ const char *name;
+ GLenum format;
+ GLenum type;
+ GLint bytes;
+ GLuint redTexel, greenTexel;
+};
+
+static const struct pixel_format Formats[] = {
+
+ { "GL_RGBA/GL_UNSIGNED_INT_8_8_8_8",
+ GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, 4, 0xff000000, 0x00ff0000 },
+ { "GL_RGBA/GL_UNSIGNED_INT_8_8_8_8_REV",
+ GL_RGBA, GL_UNSIGNED_INT_8_8_8_8_REV, 4, 0x000000ff, 0x0000ff00 },
+ { "GL_RGBA/GL_UNSIGNED_INT_10_10_10_2",
+ GL_RGBA, GL_UNSIGNED_INT_10_10_10_2, 4, 0xffc00000, 0x3ff000 },
+ { "GL_RGBA/GL_UNSIGNED_INT_2_10_10_10_REV",
+ GL_RGBA, GL_UNSIGNED_INT_2_10_10_10_REV, 4, 0x3ff, 0xffc00 },
+ { "GL_RGBA/GL_UNSIGNED_SHORT_4_4_4_4",
+ GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4, 2, 0xf000, 0x0f00 },
+ { "GL_RGBA/GL_UNSIGNED_SHORT_4_4_4_4_REV",
+ GL_RGBA, GL_UNSIGNED_SHORT_4_4_4_4_REV, 2, 0x000f, 0x00f0 },
+ { "GL_RGBA/GL_UNSIGNED_SHORT_5_5_5_1",
+ GL_RGBA, GL_UNSIGNED_SHORT_5_5_5_1, 2, 0xf800, 0x7c0 },
+ { "GL_RGBA/GL_UNSIGNED_SHORT_1_5_5_5_REV",
+ GL_RGBA, GL_UNSIGNED_SHORT_1_5_5_5_REV, 2, 0x1f, 0x3e0 },
+
+ { "GL_BGRA/GL_UNSIGNED_INT_8_8_8_8",
+ GL_BGRA, GL_UNSIGNED_INT_8_8_8_8, 4, 0x0000ff00, 0x00ff0000 },
+ { "GL_BGRA/GL_UNSIGNED_INT_8_8_8_8_REV",
+ GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, 4, 0x00ff0000, 0x0000ff00 },
+ { "GL_BGRA/GL_UNSIGNED_SHORT_4_4_4_4",
+ GL_BGRA, GL_UNSIGNED_SHORT_4_4_4_4, 2, 0x00f0, 0x0f00 },
+ { "GL_BGRA/GL_UNSIGNED_SHORT_4_4_4_4_REV",
+ GL_BGRA, GL_UNSIGNED_SHORT_4_4_4_4_REV, 2, 0x0f00, 0x00f0 },
+ { "GL_BGRA/GL_UNSIGNED_SHORT_5_5_5_1",
+ GL_BGRA, GL_UNSIGNED_SHORT_5_5_5_1, 2, 0x3e, 0x7c0 },
+ { "GL_BGRA/GL_UNSIGNED_SHORT_1_5_5_5_REV",
+ GL_BGRA, GL_UNSIGNED_SHORT_1_5_5_5_REV, 2, 0x7c00, 0x3e0 },
+
+ { "GL_ABGR_EXT/GL_UNSIGNED_INT_8_8_8_8",
+ GL_ABGR_EXT, GL_UNSIGNED_INT_8_8_8_8, 4, 0x000000ff, 0x0000ff00 },
+ { "GL_ABGR_EXT/GL_UNSIGNED_INT_8_8_8_8_REV",
+ GL_ABGR_EXT, GL_UNSIGNED_INT_8_8_8_8_REV, 4, 0xff000000, 0x00ff0000 },
+ { "GL_ABGR_EXT/GL_UNSIGNED_SHORT_4_4_4_4",
+ GL_ABGR_EXT, GL_UNSIGNED_SHORT_4_4_4_4, 2, 0x000f, 0x00f0 },
+ { "GL_ABGR_EXT/GL_UNSIGNED_SHORT_4_4_4_4_REV",
+ GL_ABGR_EXT, GL_UNSIGNED_SHORT_4_4_4_4_REV, 2, 0xf000, 0x0f00 },
+ { "GL_ABGR_EXT/GL_UNSIGNED_SHORT_5_5_5_1",
+ GL_ABGR_EXT, GL_UNSIGNED_SHORT_5_5_5_1, 2, 0x1, 0x3e },
+ { "GL_ABGR_EXT/GL_UNSIGNED_SHORT_1_5_5_5_REV",
+ GL_ABGR_EXT, GL_UNSIGNED_SHORT_1_5_5_5_REV, 2, 0x8000, 0x7c00 },
+
+ { "GL_RGB/GL_UNSIGNED_SHORT_5_6_5",
+ GL_RGB, GL_UNSIGNED_SHORT_5_6_5, 2, 0xf800, 0x7e0 },
+ { "GL_RGB/GL_UNSIGNED_SHORT_5_6_5_REV",
+ GL_RGB, GL_UNSIGNED_SHORT_5_6_5_REV, 2, 0x1f, 0x7e0 },
+ { "GL_RGB/GL_UNSIGNED_BYTE_3_3_2",
+ GL_RGB, GL_UNSIGNED_BYTE_3_3_2, 1, 0xe0, 0x1c },
+ { "GL_RGB/GL_UNSIGNED_BYTE_2_3_3_REV",
+ GL_RGB, GL_UNSIGNED_BYTE_2_3_3_REV, 1, 0x7, 0x38 },
+
+ { NULL, 0, 0, 0, 0, 0 }
+};
+
+
+struct name_format {
+ const char *name;
+ GLenum format;
+};
+
+static const struct name_format IntFormats[] = {
+ { "GL_RGBA", GL_RGBA },
+ { "GL_RGBA2", GL_RGBA2 },
+ { "GL_RGBA4", GL_RGBA4 },
+ { "GL_RGB5_A1", GL_RGB5_A1 },
+ { "GL_RGBA8", GL_RGBA8 },
+ { "GL_RGBA12", GL_RGBA12 },
+ { "GL_RGBA16", GL_RGBA16 },
+ { "GL_RGB10_A2", GL_RGB10_A2 },
+
+ { "GL_RGB", GL_RGB },
+ { "GL_R3_G3_B2", GL_R3_G3_B2 },
+ { "GL_RGB4", GL_RGB4 },
+ { "GL_RGB5", GL_RGB5 },
+ { "GL_RGB8", GL_RGB8 },
+ { "GL_RGB10", GL_RGB10 },
+ { "GL_RGB12", GL_RGB12 },
+ { "GL_RGB16", GL_RGB16 },
+
+};
+
+#define NUM_INT_FORMATS (sizeof(IntFormats) / sizeof(IntFormats[0]))
+static GLuint CurFormat = 0;
+
+
+static void
+PrintString(const char *s)
+{
+ while (*s) {
+ glutBitmapCharacter(GLUT_BITMAP_8_BY_13, (int) *s);
+ s++;
+ }
+}
+
+
+static void
+MakeTexture(const struct pixel_format *format, GLenum intFormat, GLboolean swap)
+{
+ GLubyte texBuffer[1000];
+ int i;
+
+ glPixelStorei(GL_UNPACK_SWAP_BYTES, swap);
+
+ if (format->bytes == 1) {
+ for (i = 0; i < 8; i++) {
+ texBuffer[i] = format->redTexel;
+ }
+ for (i = 8; i < 16; i++) {
+ texBuffer[i] = format->greenTexel;
+ }
+ }
+ else if (format->bytes == 2) {
+ GLushort *us = (GLushort *) texBuffer;
+ for (i = 0; i < 8; i++) {
+ us[i] = format->redTexel;
+ }
+ for (i = 8; i < 16; i++) {
+ us[i] = format->greenTexel;
+ }
+ if (swap) {
+ for (i = 0; i < 16; i++)
+ us[i] = (us[i] << 8) | (us[i] >> 8);
+ }
+ }
+ else if (format->bytes == 4) {
+ GLuint *ui = (GLuint *) texBuffer;
+ for (i = 0; i < 8; i++) {
+ ui[i] = format->redTexel;
+ }
+ for (i = 8; i < 16; i++) {
+ ui[i] = format->greenTexel;
+ }
+ if (swap) {
+ for (i = 0; i < 16; i++) {
+ GLuint b = ui[i];
+ ui[i] = (b >> 24)
+ | ((b >> 8) & 0xff00)
+ | ((b << 8) & 0xff0000)
+ | ((b << 24) & 0xff000000);
+ }
+ }
+ }
+ else {
+ abort();
+ }
+ glTexImage2D(GL_TEXTURE_2D, 0, intFormat, 4, 4, 0,
+ format->format, format->type, texBuffer);
+
+ if (glGetError()) {
+ printf("GL Error for %s\n", format->name);
+ memset(texBuffer, 255, 1000);
+ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 4, 4, 0,
+ GL_RGB, GL_UNSIGNED_BYTE, texBuffer);
+ }
+}
+
+
+
+static void
+Draw(void)
+{
+ char s[1000];
+ int w = 350, h = 20;
+ int i, swap;
+
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ for (swap = 0; swap < 2; swap++) {
+ for (i = 0; Formats[i].name; i++) {
+ glPushMatrix();
+ glTranslatef(swap * (w + 2), i * (h + 2), 0);
+
+ MakeTexture(Formats + i, IntFormats[CurFormat].format, swap);
+
+ glEnable(GL_TEXTURE_2D);
+ glBegin(GL_POLYGON);
+ glTexCoord2f(0, 0); glVertex2f(0, 0);
+ glTexCoord2f(1, 0); glVertex2f(w, 0);
+ glTexCoord2f(1, 1); glVertex2f(w, h);
+ glTexCoord2f(0, 1); glVertex2f(0, h);
+ glEnd();
+
+ glDisable(GL_TEXTURE_2D);
+ glColor3f(0, 0, 0);
+ glRasterPos2i(8, 6);
+ PrintString(Formats[i].name);
+
+ glPopMatrix();
+ }
+ }
+
+ glPushMatrix();
+ glTranslatef(2, i * (h + 2), 0);
+ glColor3f(1, 1, 1);
+ glRasterPos2i(8, 6);
+ PrintString("Normal");
+ glRasterPos2i(w + 2, 6);
+ PrintString("Byte Swapped");
+ glPopMatrix();
+
+ glPushMatrix();
+ glTranslatef(2, (i + 1) * (h + 2), 0);
+ glRasterPos2i(8, 6);
+ sprintf(s, "Internal Texture Format [f/F]: %s (%d of %d)",
+ IntFormats[CurFormat].name, CurFormat + 1, NUM_INT_FORMATS);
+ PrintString(s);
+ glPopMatrix();
+
+ glutSwapBuffers();
+}
+
+
+static void
+Reshape(int width, int height)
+{
+ glViewport(0, 0, width, height);
+ glMatrixMode(GL_PROJECTION);
+ glLoadIdentity();
+ glOrtho(0, width, 0, height, -1, 1);
+ glMatrixMode(GL_MODELVIEW);
+ glLoadIdentity();
+}
+
+
+static void
+Key(unsigned char key, int x, int y)
+{
+ (void) x;
+ (void) y;
+ switch (key) {
+ case 'F':
+ if (CurFormat == 0)
+ CurFormat = NUM_INT_FORMATS - 1;
+ else
+ CurFormat--;
+ break;
+ case 'f':
+ CurFormat++;
+ if (CurFormat == NUM_INT_FORMATS)
+ CurFormat = 0;
+ break;
+ case 27:
+ exit(0);
+ break;
+ }
+ glutPostRedisplay();
+}
+
+
+static void
+Init(void)
+{
+ printf("GL_RENDERER = %s\n", (char *) glGetString(GL_RENDERER));
+ printf("GL_VERSION = %s\n", (char *) glGetString(GL_VERSION));
+ 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_REPLACE);
+}
+
+
+int
+main(int argc, char *argv[])
+{
+ glutInit(&argc, argv);
+ glutInitWindowPosition(0, 0);
+ glutInitWindowSize(700, 800);
+ glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
+ glutCreateWindow(argv[0]);
+ glutReshapeFunc(Reshape);
+ glutKeyboardFunc(Key);
+ glutDisplayFunc(Draw);
+ Init();
+ glutMainLoop();
+ return 0;
+}