From ae9087aea7aa2b19bf78daa6593d14dfba98183d Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Wed, 28 Aug 2024 03:48:19 +0100
Subject: Initial cut of shadow map creation with support for billboard shadows

---
 gfx/gl/shaders/shadowDynamicPointStencil.fs | 16 +++++++++++++++
 gfx/gl/shaders/shadowDynamicPointStencil.gs | 32 +++++++++++++++++++++++++++++
 gfx/gl/shaders/shadowDynamicPointStencil.vs | 17 +++++++++++++++
 3 files changed, 65 insertions(+)
 create mode 100644 gfx/gl/shaders/shadowDynamicPointStencil.fs
 create mode 100644 gfx/gl/shaders/shadowDynamicPointStencil.gs
 create mode 100644 gfx/gl/shaders/shadowDynamicPointStencil.vs

(limited to 'gfx/gl/shaders')

diff --git a/gfx/gl/shaders/shadowDynamicPointStencil.fs b/gfx/gl/shaders/shadowDynamicPointStencil.fs
new file mode 100644
index 0000000..57b8aa3
--- /dev/null
+++ b/gfx/gl/shaders/shadowDynamicPointStencil.fs
@@ -0,0 +1,16 @@
+#version 330 core
+#extension GL_ARB_shading_language_420pack : enable
+
+layout(binding = 0) uniform sampler2D stencilDepth;
+flat in vec3 scale;
+in vec2 texCoord;
+
+void
+main()
+{
+	float stDepth = texture(stencilDepth, texCoord).r;
+	if (stDepth >= 1) {
+		discard;
+	}
+	gl_FragDepth = gl_FragCoord.z + (stDepth * scale.z);
+}
diff --git a/gfx/gl/shaders/shadowDynamicPointStencil.gs b/gfx/gl/shaders/shadowDynamicPointStencil.gs
new file mode 100644
index 0000000..6d707ae
--- /dev/null
+++ b/gfx/gl/shaders/shadowDynamicPointStencil.gs
@@ -0,0 +1,32 @@
+#version 330 core
+#extension GL_ARB_viewport_array : enable
+
+const vec2[] corners = vec2[4](vec2(-1, -1), vec2(-1, 1), vec2(1, -1), vec2(1, 1));
+
+uniform mat4 viewProjection[4];
+uniform int viewProjections;
+uniform vec3 sizes[4];
+uniform float size;
+
+in ivec3 vworldPos[];
+
+flat out vec3 scale;
+out vec2 texCoord;
+
+layout(points) in;
+layout(triangle_strip, max_vertices = 16) out;
+
+void
+main()
+{
+	for (gl_Layer = 0; gl_Layer < viewProjections; ++gl_Layer) {
+		scale = 2.0 * size / sizes[gl_Layer];
+		vec4 pos = viewProjection[gl_Layer] * vec4(vworldPos[0], 1);
+		for (int c = 0; c < corners.length(); ++c) {
+			gl_Position = pos + vec4(scale.xy * corners[c], 0, 0);
+			texCoord = (corners[c] * 0.5) + 0.5;
+			EmitVertex();
+		}
+		EndPrimitive();
+	}
+}
diff --git a/gfx/gl/shaders/shadowDynamicPointStencil.vs b/gfx/gl/shaders/shadowDynamicPointStencil.vs
new file mode 100644
index 0000000..dadf9c2
--- /dev/null
+++ b/gfx/gl/shaders/shadowDynamicPointStencil.vs
@@ -0,0 +1,17 @@
+#version 330 core
+#extension GL_ARB_shading_language_420pack : enable
+
+layout(location = 0) in mat3 model;
+layout(location = 3) in ivec3 worldPos;
+uniform ivec3 viewPoint;
+uniform vec3 centre;
+
+out mat3 vmodel;
+out ivec3 vworldPos;
+
+void
+main()
+{
+	vmodel = model;
+	vworldPos = worldPos - viewPoint + ivec3(centre);
+}
-- 
cgit v1.2.3