gl_shader_gen: simplify and clarify the depth transformation between vertex shader and fragment shader

This commit is contained in:
wwylele 2017-08-17 10:56:15 +03:00
parent 1eca380886
commit 5a4af616c6

View file

@ -1112,7 +1112,10 @@ vec4 secondary_fragment_color = vec4(0.0);
"gl_FragCoord.y < scissor_y2)) discard;\n";
}
out += "float z_over_w = 1.0 - gl_FragCoord.z * 2.0;\n";
// After perspective divide, OpenGL transform z_over_w from [-1, 1] to [near, far]. Here we use
// default near = 0 and far = 1, and undo the transformation to get the original z_over_w, then
// do our own transformation according to PICA specification.
out += "float z_over_w = 2.0 * gl_FragCoord.z - 1.0;\n";
out += "float depth = z_over_w * depth_scale + depth_offset;\n";
if (state.depthmap_enable == RasterizerRegs::DepthBuffering::WBuffering) {
out += "depth /= gl_FragCoord.w;\n";
@ -1195,7 +1198,7 @@ void main() {
texcoord0_w = vert_texcoord0_w;
normquat = vert_normquat;
view = vert_view;
gl_Position = vec4(vert_position.x, vert_position.y, -vert_position.z, vert_position.w);
gl_Position = vert_position;
gl_ClipDistance[0] = -vert_position.z; // fixed PICA clipping plane z <= 0
// TODO (wwylele): calculate gl_ClipDistance[1] from user-defined clipping plane
}