1 files changed, 188 insertions, 0 deletions
diff --git a/servers/rendering/rasterizer_rd/shaders/cubemap_downsampler.glsl b/servers/rendering/rasterizer_rd/shaders/cubemap_downsampler.glsl
new file mode 100644
index 0000000000..9f3ecf6053
--- /dev/null
+++ b/servers/rendering/rasterizer_rd/shaders/cubemap_downsampler.glsl
@@ -0,0 +1,188 @@
+// Copyright 2016 Activision Publishing, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining
+// a copy of this software and associated documentation files (the "Software"),
+// to deal in the Software without restriction, including without limitation
+// the rights to use, copy, modify, merge, publish, distribute, sublicense,
+// and/or sell copies of the Software, and to permit persons to whom the Software
+// is furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in all
+// copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+// SOFTWARE.
+
+/* clang-format off */
+[compute]
+
+#version 450
+
+VERSION_DEFINES
+
+#define BLOCK_SIZE 8
+
+layout(local_size_x = BLOCK_SIZE, local_size_y = BLOCK_SIZE, local_size_z = 1) in;
+/* clang-format on */
+
+layout(set = 0, binding = 0) uniform samplerCube source_cubemap;
+
+layout(rgba16f, set = 1, binding = 0) uniform restrict writeonly imageCube dest_cubemap;
+
+layout(push_constant, binding = 1, std430) uniform Params {
+	uint face_size;
+}
+params;
+
+#define M_PI 3.14159265359
+
+void get_dir_0(out vec3 dir, in float u, in float v) {
+	dir[0] = 1.0;
+	dir[1] = v;
+	dir[2] = -u;
+}
+void get_dir_1(out vec3 dir, in float u, in float v) {
+	dir[0] = -1.0;
+	dir[1] = v;
+	dir[2] = u;
+}
+void get_dir_2(out vec3 dir, in float u, in float v) {
+	dir[0] = u;
+	dir[1] = 1.0;
+	dir[2] = -v;
+}
+void get_dir_3(out vec3 dir, in float u, in float v) {
+	dir[0] = u;
+	dir[1] = -1.0;
+	dir[2] = v;
+}
+void get_dir_4(out vec3 dir, in float u, in float v) {
+	dir[0] = u;
+	dir[1] = v;
+	dir[2] = 1.0;
+}
+void get_dir_5(out vec3 dir, in float u, in float v) {
+	dir[0] = -u;
+	dir[1] = v;
+	dir[2] = -1.0;
+}
+
+float calcWeight(float u, float v) {
+	float val = u * u + v * v + 1.0;
+	return val * sqrt(val);
+}
+
+void main() {
+	uvec3 id = gl_GlobalInvocationID;
+	uint face_size = params.face_size;
+
+	if (id.x < face_size && id.y < face_size) {
+		float inv_face_size = 1.0 / float(face_size);
+
+		float u0 = (float(id.x) * 2.0 + 1.0 - 0.75) * inv_face_size - 1.0;
+		float u1 = (float(id.x) * 2.0 + 1.0 + 0.75) * inv_face_size - 1.0;
+
+		float v0 = (float(id.y) * 2.0 + 1.0 - 0.75) * -inv_face_size + 1.0;
+		float v1 = (float(id.y) * 2.0 + 1.0 + 0.75) * -inv_face_size + 1.0;
+
+		float weights[4];
+		weights[0] = calcWeight(u0, v0);
+		weights[1] = calcWeight(u1, v0);
+		weights[2] = calcWeight(u0, v1);
+		weights[3] = calcWeight(u1, v1);
+
+		const float wsum = 0.5 / (weights[0] + weights[1] + weights[2] + weights[3]);
+		for (int i = 0; i < 4; i++) {
+			weights[i] = weights[i] * wsum + .125;
+		}
+
+		vec3 dir;
+		vec4 color;
+		switch (id.z) {
+			case 0:
+				get_dir_0(dir, u0, v0);
+				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+				get_dir_0(dir, u1, v0);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+				get_dir_0(dir, u0, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+				get_dir_0(dir, u1, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+				break;
+			case 1:
+				get_dir_1(dir, u0, v0);
+				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+				get_dir_1(dir, u1, v0);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+				get_dir_1(dir, u0, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+				get_dir_1(dir, u1, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+				break;
+			case 2:
+				get_dir_2(dir, u0, v0);
+				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+				get_dir_2(dir, u1, v0);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+				get_dir_2(dir, u0, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+				get_dir_2(dir, u1, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+				break;
+			case 3:
+				get_dir_3(dir, u0, v0);
+				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+				get_dir_3(dir, u1, v0);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+				get_dir_3(dir, u0, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+				get_dir_3(dir, u1, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+				break;
+			case 4:
+				get_dir_4(dir, u0, v0);
+				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+				get_dir_4(dir, u1, v0);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+				get_dir_4(dir, u0, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+				get_dir_4(dir, u1, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+				break;
+			default:
+				get_dir_5(dir, u0, v0);
+				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+				get_dir_5(dir, u1, v0);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+				get_dir_5(dir, u0, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+				get_dir_5(dir, u1, v1);
+				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+				break;
+		}
+		imageStore(dest_cubemap, ivec3(id), color);
+	}
+}