#include <stdio.h>
#include <stdlib.h>
#include <string.h>
+#include <GL/glew.h>
#include "GL/glut.h"
#include "readtex.h"
#include "extfuncs.h"
static GLuint Program;
-static GLfloat Xrot = -90.0, Yrot = .0, Zrot = 0.0;
+static GLfloat Xrot = 0.0, Yrot = .0, Zrot = 0.0;
static GLfloat EyeDist = 10;
static GLboolean Anim = GL_TRUE;
+static GLboolean UseArrays = GL_TRUE;
+
+static GLint VertCoord_attr = -1, TexCoord0_attr = -1, TexCoord1_attr = -1;
/* value[0] = tex unit */
};
+static const GLfloat Tex0Coords[4][2] = {
+ { 0.0, 0.0 }, { 2.0, 0.0 }, { 2.0, 2.0 }, { 0.0, 2.0 }
+};
+
+static const GLfloat Tex1Coords[4][2] = {
+ { 0.0, 0.0 }, { 1.0, 0.0 }, { 1.0, 1.0 }, { 0.0, 1.0 }
+};
+
+static const GLfloat VertCoords[4][2] = {
+ { -3.0, -3.0 }, { 3.0, -3.0 }, { 3.0, 3.0 }, { -3.0, 3.0 }
+};
+
+
static void
-DrawPolygon(GLfloat size)
+DrawPolygonArray(void)
{
- glPushMatrix();
- glRotatef(90, 1, 0, 0);
- glNormal3f(0, 0, 1);
- glBegin(GL_POLYGON);
+ if (VertCoord_attr >= 0) {
+ glVertexAttribPointer_func(VertCoord_attr, 2, GL_FLOAT, GL_FALSE,
+ 0, VertCoords);
+ glEnableVertexAttribArray_func(VertCoord_attr);
+ }
+ else {
+ glVertexPointer(2, GL_FLOAT, 0, VertCoords);
+ glEnable(GL_VERTEX_ARRAY);
+ }
+
+ glVertexAttribPointer_func(TexCoord0_attr, 2, GL_FLOAT, GL_FALSE,
+ 0, Tex0Coords);
+ glEnableVertexAttribArray_func(TexCoord0_attr);
+
+ glVertexAttribPointer_func(TexCoord1_attr, 2, GL_FLOAT, GL_FALSE,
+ 0, Tex1Coords);
+ glEnableVertexAttribArray_func(TexCoord1_attr);
+
+ glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+}
- glMultiTexCoord2f(GL_TEXTURE0, 0, 0);
- glMultiTexCoord2f(GL_TEXTURE1, 0, 0);
- glVertex2f(-size, -size);
- glMultiTexCoord2f(GL_TEXTURE0, 2, 0);
- glMultiTexCoord2f(GL_TEXTURE1, 1, 0);
- glVertex2f( size, -size);
+static void
+DrawPolygonVert(void)
+{
+ GLuint i;
- glMultiTexCoord2f(GL_TEXTURE0, 2, 2);
- glMultiTexCoord2f(GL_TEXTURE1, 1, 1);
- glVertex2f( size, size);
+ glBegin(GL_TRIANGLE_FAN);
- glMultiTexCoord2f(GL_TEXTURE0, 0, 2);
- glMultiTexCoord2f(GL_TEXTURE1, 0, 1);
- glVertex2f(-size, size);
+ for (i = 0; i < 4; i++) {
+ glVertexAttrib2fv_func(TexCoord0_attr, Tex0Coords[i]);
+ glVertexAttrib2fv_func(TexCoord1_attr, Tex1Coords[i]);
+
+ if (VertCoord_attr >= 0)
+ glVertexAttrib2fv_func(VertCoord_attr, VertCoords[i]);
+ else
+ glVertex2fv(VertCoords[i]);
+ }
glEnd();
- glPopMatrix();
}
glRotatef(Yrot, 0, 1, 0);
glRotatef(Xrot, 1, 0, 0);
- DrawPolygon(3.0);
+ if (UseArrays)
+ DrawPolygonArray();
+ else
+ DrawPolygonVert();
glPopMatrix();
(void) x;
(void) y;
switch (k) {
- case ' ':
case 'a':
+ UseArrays = !UseArrays;
+ printf("Arrays: %d\n", UseArrays);
+ break;
+ case ' ':
Anim = !Anim;
if (Anim)
glutIdleFunc(idle);
InitUniforms(program, uniforms);
+ VertCoord_attr = glGetAttribLocation_func(program, "VertCoord");
+ if (VertCoord_attr > 0) {
+ /* We want the VertCoord attrib to have position zero so that
+ * the call to glVertexAttrib(0, xyz) triggers vertex processing.
+ * Otherwise, if TexCoord0 or TexCoord1 gets position 0 we'd have
+ * to set that attribute last (which is a PITA to manage).
+ */
+ glBindAttribLocation_func(program, 0, "VertCoord");
+ /* re-link */
+ glLinkProgram_func(program);
+ /* VertCoord_attr should be zero now */
+ VertCoord_attr = glGetAttribLocation_func(program, "VertCoord");
+ assert(VertCoord_attr == 0);
+ }
+
+ TexCoord0_attr = glGetAttribLocation_func(program, "TexCoord0");
+ TexCoord1_attr = glGetAttribLocation_func(program, "TexCoord1");
+
+ printf("TexCoord0_attr = %d\n", TexCoord0_attr);
+ printf("TexCoord1_attr = %d\n", TexCoord1_attr);
+ printf("VertCoord_attr = %d\n", VertCoord_attr);
+
return program;
}
glutInitWindowSize(500, 400);
glutInitDisplayMode(GLUT_RGB | GLUT_DEPTH | GLUT_DOUBLE);
glutCreateWindow(Demo);
+ glewInit();
glutReshapeFunc(Reshape);
glutKeyboardFunc(key);
glutSpecialFunc(specialkey);