Mesa (master): progs: add trivial ARB_half_float_vertex support.

Dave Airlie airlied at kemper.freedesktop.org
Fri Jan 22 18:31:30 PST 2010


Module: Mesa
Branch: master
Commit: dcaf6687e8b27f2f988da757665ca922071db47f
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=dcaf6687e8b27f2f988da757665ca922071db47f

Author: Dave Airlie <airlied at linux.ie>
Date:   Mon Jan 18 16:25:30 2010 +1000

progs: add trivial ARB_half_float_vertex support.

This is just a trivial port of vp-array.c

Signed-off-by: Dave Airlie <airlied at redhat.com>

---

 progs/trivial/Makefile      |    1 +
 progs/trivial/vp-array-hf.c |  215 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 216 insertions(+), 0 deletions(-)

diff --git a/progs/trivial/Makefile b/progs/trivial/Makefile
index 5e08d60..207215d 100644
--- a/progs/trivial/Makefile
+++ b/progs/trivial/Makefile
@@ -160,6 +160,7 @@ SOURCES = \
 	vbo-drawelements.c \
 	vbo-drawrange.c \
 	vp-array.c \
+	vp-array-hf.c \
 	vp-array-int.c \
 	vp-clip.c \
 	vp-line-clip.c \
diff --git a/progs/trivial/vp-array-hf.c b/progs/trivial/vp-array-hf.c
new file mode 100644
index 0000000..f812436
--- /dev/null
+++ b/progs/trivial/vp-array-hf.c
@@ -0,0 +1,215 @@
+/* Test glGenProgramsNV(), glIsProgramNV(), glLoadProgramNV() */
+
+#include <assert.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <GL/glew.h>
+#include <GL/glut.h>
+
+typedef union { GLfloat f; GLint i; } fi_type;
+/**
+ * Convert a 4-byte float to a 2-byte half float.
+ * Based on code from:
+ * http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/008786.html
+ */
+static GLhalf
+_mesa_float_to_half(GLfloat val)
+{
+
+   const fi_type fi = {val};
+   const int flt_m = fi.i & 0x7fffff;
+   const int flt_e = (fi.i >> 23) & 0xff;
+   const int flt_s = (fi.i >> 31) & 0x1;
+   int s, e, m = 0;
+   GLhalf result;
+   
+   /* sign bit */
+   s = flt_s;
+
+   /* handle special cases */
+   if ((flt_e == 0) && (flt_m == 0)) {
+      /* zero */
+      /* m = 0; - already set */
+      e = 0;
+   }
+   else if ((flt_e == 0) && (flt_m != 0)) {
+      /* denorm -- denorm float maps to 0 half */
+      /* m = 0; - already set */
+      e = 0;
+   }
+   else if ((flt_e == 0xff) && (flt_m == 0)) {
+      /* infinity */
+      /* m = 0; - already set */
+      e = 31;
+   }
+   else if ((flt_e == 0xff) && (flt_m != 0)) {
+      /* NaN */
+      m = 1;
+      e = 31;
+   }
+   else {
+      /* regular number */
+      const int new_exp = flt_e - 127;
+      if (new_exp < -24) {
+         /* this maps to 0 */
+         /* m = 0; - already set */
+         e = 0;
+      }
+      else if (new_exp < -14) {
+         /* this maps to a denorm */
+         unsigned int exp_val = (unsigned int) (-14 - new_exp); /* 2^-exp_val*/
+         e = 0;
+         switch (exp_val) {
+            case 0:
+               /* m = 0; - already set */
+               break;
+            case 1: m = 512 + (flt_m >> 14); break;
+            case 2: m = 256 + (flt_m >> 15); break;
+            case 3: m = 128 + (flt_m >> 16); break;
+            case 4: m = 64 + (flt_m >> 17); break;
+            case 5: m = 32 + (flt_m >> 18); break;
+            case 6: m = 16 + (flt_m >> 19); break;
+            case 7: m = 8 + (flt_m >> 20); break;
+            case 8: m = 4 + (flt_m >> 21); break;
+            case 9: m = 2 + (flt_m >> 22); break;
+            case 10: m = 1; break;
+         }
+      }
+      else if (new_exp > 15) {
+         /* map this value to infinity */
+         /* m = 0; - already set */
+         e = 31;
+      }
+      else {
+         /* regular */
+         e = new_exp + 15;
+         m = flt_m >> 13;
+      }
+   }
+
+   result = (s << 15) | (e << 10) | m;
+   return result;
+}
+
+
+GLfloat verts[][4] = {
+   {  0.9, -0.9, 0.0, 1.0 },
+   {  0.9,  0.9, 0.0, 1.0 },
+   { -0.9,  0.9, 0.0, 1.0 },
+   { -0.9, -0.9, 0.0, 1.0 },
+};
+
+GLhalf hverts[16];
+
+GLubyte color[][4] = {
+   { 0x00, 0x00, 0xff, 0x00 },
+   { 0x00, 0xff, 0x00, 0x00 },
+   { 0xff, 0x00, 0x00, 0x00 },
+   { 0xff, 0xff, 0xff, 0x00 },
+};
+
+GLuint indices[] = { 0, 1, 2, 3 };
+
+static void Init( void )
+{
+   GLint errno;
+   GLuint prognum;
+   GLuint i, j;
+
+   static const char *prog1 =
+      "!!ARBvp1.0\n"
+      "MOV  result.color, vertex.color;\n"
+      "MOV  result.position, vertex.position;\n"
+      "END\n";
+
+   if (!glutExtensionSupported("GL_ARB_half_float_vertex")) {
+      printf("GL_ARB_half_float_vertex not found!\n");
+      exit(0);
+   }
+
+   glGenProgramsARB(1, &prognum);
+   glBindProgramARB(GL_VERTEX_PROGRAM_ARB, prognum);
+   glProgramStringARB(GL_VERTEX_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB,
+		      strlen(prog1), (const GLubyte *) prog1);
+
+   assert(glIsProgramARB(prognum));
+   errno = glGetError();
+   printf("glGetError = %d\n", errno);
+   if (errno != GL_NO_ERROR)
+   {
+      GLint errorpos;
+
+      glGetIntegerv(GL_PROGRAM_ERROR_POSITION_ARB, &errorpos);
+      printf("errorpos: %d\n", errorpos);
+      printf("%s\n", (char *)glGetString(GL_PROGRAM_ERROR_STRING_ARB));
+   }
+
+   for (i = 0; i < 4; i++)
+      for (j = 0; j < 4; j++)
+	 hverts[i * 4 + j] = _mesa_float_to_half(verts[i][j]);
+
+   glEnableClientState( GL_VERTEX_ARRAY );
+   glEnableClientState( GL_COLOR_ARRAY );
+   glVertexPointer( 4, GL_HALF_FLOAT, 8, hverts );
+   glColorPointer( 4, GL_UNSIGNED_BYTE, 0, color );
+
+}
+
+
+
+static void Display( void )
+{
+   glClearColor(0.3, 0.3, 0.3, 1);
+   glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
+
+   glEnable(GL_VERTEX_PROGRAM_NV);
+   glDrawElements( GL_TRIANGLES, 3, GL_UNSIGNED_INT, indices );
+
+   glFlush(); 
+}
+
+
+static void Reshape( int width, int height )
+{
+   glViewport( 0, 0, width, height );
+   glMatrixMode( GL_PROJECTION );
+   glLoadIdentity();
+   glOrtho(-1.0, 1.0, -1.0, 1.0, -0.5, 1000.0);
+   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 27:
+         exit(0);
+         break;
+   }
+   glutPostRedisplay();
+}
+
+
+
+
+int main( int argc, char *argv[] )
+{
+   glutInit( &argc, argv );
+   glutInitWindowPosition( 0, 0 );
+   glutInitWindowSize( 250, 250 );
+   glutInitDisplayMode( GLUT_RGB | GLUT_SINGLE | GLUT_DEPTH );
+   glutCreateWindow(argv[0]);
+   glewInit();
+   glutReshapeFunc( Reshape );
+   glutKeyboardFunc( Key );
+   glutDisplayFunc( Display );
+   Init();
+   glutMainLoop();
+   return 0;
+}



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