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demos: modify bufferobj.c to exercise interleaved vertex arrays

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Also, put colors before vertex positions, and place the data at a 40-byte
offset from the start of the buffer.
This commit is contained in:
Brian Paul
2009-02-03 15:17:26 -07:00
parent 8e8b25c26a
commit dd22f6f795
1 changed files with 23 additions and 13 deletions
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36
progs/tests/bufferobj.c
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@@ -22,6 +22,8 @@ struct object
GLuint NumVerts;
GLuint VertexOffset;
GLuint ColorOffset;
GLuint VertexStride;
GLuint ColorStride;
GLuint NumElements;
};
@@ -46,7 +48,7 @@ static void CheckError(int line)
static void DrawObject( const struct object *obj )
{
glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
glVertexPointer(3, GL_FLOAT, 0, (void *) obj->VertexOffset);
glVertexPointer(3, GL_FLOAT, obj->VertexStride, (void *) obj->VertexOffset);
glEnable(GL_VERTEX_ARRAY);
/* test push/pop attrib */
@@ -60,7 +62,7 @@ static void DrawObject( const struct object *obj )
glPopClientAttrib();
}
#endif
glColorPointer(3, GL_FLOAT, 0, (void *) obj->ColorOffset);
glColorPointer(3, GL_FLOAT, obj->ColorStride, (void *) obj->ColorOffset);
glEnable(GL_COLOR_ARRAY);
if (obj->NumElements > 0) {
@@ -241,6 +243,8 @@ static void MakeObject1(struct object *obj)
obj->NumVerts = 4;
obj->VertexOffset = 0;
obj->ColorOffset = 3 * sizeof(GLfloat) * obj->NumVerts;
obj->VertexStride = 0;
obj->ColorStride = 0;
obj->NumElements = 0;
glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
@@ -255,24 +259,28 @@ static void MakeObject1(struct object *obj)
static void MakeObject2(struct object *obj)
{
GLfloat *v, *c;
GLfloat *v;
int start = 40; /* bytes, to test non-zero array offsets */
glGenBuffersARB(1, &obj->BufferID);
glBindBufferARB(GL_ARRAY_BUFFER_ARB, obj->BufferID);
glBufferDataARB(GL_ARRAY_BUFFER_ARB, 1000, NULL, GL_STATIC_DRAW_ARB);
v = (GLfloat *) glMapBufferARB(GL_ARRAY_BUFFER_ARB, GL_WRITE_ONLY_ARB);
/* Make triangle */
v[0] = -1; v[1] = -1; v[2] = 0;
v[3] = 1; v[4] = -1; v[5] = 0;
v[6] = 0; v[7] = 1; v[8] = 0;
c = v + 9;
c[0] = 0; c[1] = 1; c[2] = 0;
c[3] = 0; c[4] = 1; c[5] = 0;
c[6] = 1; c[7] = 1; c[8] = 0;
v += start / sizeof(GLfloat);
/* Make triangle: interleaved colors, then positions */
/* R G B X Y Z */
v[0] = 0; v[1] = 1; v[2] = 0; v[3] = -1; v[4] = -1; v[5] = 0;
v[6] = 0; v[7] = 1; v[8] = 0; v[9] = 1; v[10] = -1; v[11] = 0;
v[12] = 1; v[13] = 1; v[14] = 0; v[15] = 0; v[16] = 1; v[17] = 0;
obj->NumVerts = 3;
obj->VertexOffset = 0;
obj->ColorOffset = 3 * sizeof(GLfloat) * obj->NumVerts;
obj->VertexOffset = start + 3 * sizeof(GLfloat);
obj->ColorOffset = start;
obj->VertexStride = 6 * sizeof(GLfloat);
obj->ColorStride = 6 * sizeof(GLfloat);
obj->NumElements = 0;
glUnmapBufferARB(GL_ARRAY_BUFFER_ARB);
@@ -300,6 +308,8 @@ static void MakeObject3(struct object *obj)
obj->NumVerts = 4;
obj->VertexOffset = 0;
obj->ColorOffset = 3 * sizeof(GLfloat) * obj->NumVerts;
obj->VertexStride = 0;
obj->ColorStride = 0;
bytes = obj->NumVerts * (3 + 3) * sizeof(GLfloat);