1 files changed, 54 insertions, 0 deletions
diff --git a/drivers/gles2/shaders/ssao_minify.glsl b/drivers/gles2/shaders/ssao_minify.glsl
new file mode 100644
index 0000000000..f654e00a4f
--- /dev/null
+++ b/drivers/gles2/shaders/ssao_minify.glsl
@@ -0,0 +1,54 @@
+/* clang-format off */
+[vertex]
+
+layout(location = 0) in highp vec4 vertex_attrib;
+/* clang-format on */
+
+void main() {
+	gl_Position = vertex_attrib;
+}
+
+/* clang-format off */
+[fragment]
+
+#ifdef MINIFY_START
+
+#define SDEPTH_TYPE highp sampler2D
+uniform float camera_z_far;
+uniform float camera_z_near;
+/* clang-format on */
+
+#else
+
+#define SDEPTH_TYPE mediump usampler2D
+
+#endif
+
+uniform SDEPTH_TYPE source_depth; //texunit:0
+
+uniform ivec2 from_size;
+uniform int source_mipmap;
+
+layout(location = 0) out mediump uint depth;
+
+void main() {
+	ivec2 ssP = ivec2(gl_FragCoord.xy);
+
+	// Rotated grid subsampling to avoid XY directional bias or Z precision bias while downsampling.
+	// On DX9, the bit-and can be implemented with floating-point modulo
+
+#ifdef MINIFY_START
+	float fdepth = texelFetch(source_depth, clamp(ssP * 2 + ivec2(ssP.y & 1, ssP.x & 1), ivec2(0), from_size - ivec2(1)), source_mipmap).r;
+	fdepth = fdepth * 2.0 - 1.0;
+#ifdef USE_ORTHOGONAL_PROJECTION
+	fdepth = ((fdepth + (camera_z_far + camera_z_near) / (camera_z_far - camera_z_near)) * (camera_z_far - camera_z_near)) / 2.0;
+#else
+	fdepth = 2.0 * camera_z_near * camera_z_far / (camera_z_far + camera_z_near - fdepth * (camera_z_far - camera_z_near));
+#endif
+	fdepth /= camera_z_far;
+	depth = uint(clamp(fdepth * 65535.0, 0.0, 65535.0));
+
+#else
+	depth = texelFetch(source_depth, clamp(ssP * 2 + ivec2(ssP.y & 1, ssP.x & 1), ivec2(0), from_size - ivec2(1)), source_mipmap).r;
+#endif
+}