shaders: initialize vertexes once
Create a buffer for the vertex data and place vertexes
there at initialization time. Then just use the buffer
for each texture blit.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
diff --git a/ui/shader.c b/ui/shader.c
index 52a4632..0588655 100644
--- a/ui/shader.c
+++ b/ui/shader.c
@@ -29,21 +29,42 @@
/* ---------------------------------------------------------------------- */
-void qemu_gl_run_texture_blit(GLint texture_blit_prog)
+GLuint qemu_gl_init_texture_blit(GLint texture_blit_prog)
{
- GLfloat in_position[] = {
+ static const GLfloat in_position[] = {
-1, -1,
1, -1,
-1, 1,
1, 1,
};
GLint l_position;
+ GLuint vao, buffer;
- glUseProgram(texture_blit_prog);
+ glGenVertexArrays(1, &vao);
+ glBindVertexArray(vao);
+
+ /* this is the VBO that holds the vertex data */
+ glGenBuffers(1, &buffer);
+ glBindBuffer(GL_ARRAY_BUFFER, buffer);
+ glBufferData(GL_ARRAY_BUFFER, sizeof(in_position), in_position,
+ GL_STATIC_DRAW);
+
l_position = glGetAttribLocation(texture_blit_prog, "in_position");
- glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, in_position);
+ glVertexAttribPointer(l_position, 2, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(l_position);
- glDrawArrays(GL_TRIANGLE_STRIP, l_position, 4);
+
+ glBindBuffer(GL_ARRAY_BUFFER, 0);
+ glBindVertexArray(0);
+
+ return vao;
+}
+
+void qemu_gl_run_texture_blit(GLint texture_blit_prog,
+ GLint texture_blit_vao)
+{
+ glUseProgram(texture_blit_prog);
+ glBindVertexArray(texture_blit_vao);
+ glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
}
/* ---------------------------------------------------------------------- */
