From 1e08193a1678675ac5869b76e8a2339f6de5b773 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Thu, 26 Feb 2026 18:04:06 +0000
Subject: Support for the BillboardPainter

Based on the ShadowStenciller, creates flattened images of a model for
simplified mass use in a scene.
---
 gfx/gl/shaders/billboardPainter.frag | 22 ++++++++++++++++++++++
 gfx/gl/shaders/billboardPainter.geom | 34 ++++++++++++++++++++++++++++++++++
 gfx/gl/shaders/billboardPainter.vert | 23 +++++++++++++++++++++++
 3 files changed, 79 insertions(+)
 create mode 100644 gfx/gl/shaders/billboardPainter.frag
 create mode 100644 gfx/gl/shaders/billboardPainter.geom
 create mode 100644 gfx/gl/shaders/billboardPainter.vert

(limited to 'gfx/gl/shaders')

diff --git a/gfx/gl/shaders/billboardPainter.frag b/gfx/gl/shaders/billboardPainter.frag
new file mode 100644
index 0000000..354f2ab
--- /dev/null
+++ b/gfx/gl/shaders/billboardPainter.frag
@@ -0,0 +1,22 @@
+#version 460 core
+
+layout(binding = 0) uniform sampler2D textureAlbedo;
+layout(location = 0) out vec4 bNormal;
+layout(location = 1) out vec4 bAlbedoSpec;
+
+include(`materialDetail.glsl')
+include(`materialCommon.glsl')
+in vec2 gTexCoords;
+in vec3 gNormal;
+in vec4 gColour;
+flat in MaterialDetail gMaterial;
+
+void
+main()
+{
+	vec4 textureColour = getTextureColour(gMaterial, gTexCoords);
+	float opaque = step(0.5, mix(textureColour.a, 1, gColour.a));
+	bNormal = vec4(gNormal, opaque);
+	gl_FragDepth = mix(1.0, gl_FragCoord.z, opaque);
+	bAlbedoSpec = mix(textureColour, vec4(gColour.rgb, 1), gColour.a);
+}
diff --git a/gfx/gl/shaders/billboardPainter.geom b/gfx/gl/shaders/billboardPainter.geom
new file mode 100644
index 0000000..abd5f83
--- /dev/null
+++ b/gfx/gl/shaders/billboardPainter.geom
@@ -0,0 +1,34 @@
+#version 460 core
+
+include(`materialDetail.glsl')
+
+layout(triangles) in;
+layout(triangle_strip, max_vertices = 24) out;
+
+uniform mat4 viewProjection[8];
+uniform mat4 view[8];
+in vec3 FragPos[];
+in vec2 TexCoords[];
+flat in MaterialDetail Material[];
+in vec3 Normal[];
+in vec4 Colour[];
+out vec2 gTexCoords;
+out vec3 gNormal;
+out vec4 gColour;
+flat out MaterialDetail gMaterial;
+
+void
+main()
+{
+	for (gl_Layer = 0; gl_Layer < viewProjection.length(); ++gl_Layer) {
+		for (int v = 0; v < FragPos.length(); ++v) {
+			gl_Position = viewProjection[gl_Layer] * vec4(FragPos[v], 1);
+			gNormal = (view[gl_Layer] * vec4(Normal[v], 1)).xyz;
+			gTexCoords = TexCoords[v];
+			gMaterial = Material[v];
+			gColour = Colour[v];
+			EmitVertex();
+		}
+		EndPrimitive();
+	}
+}
diff --git a/gfx/gl/shaders/billboardPainter.vert b/gfx/gl/shaders/billboardPainter.vert
new file mode 100644
index 0000000..d7c1219
--- /dev/null
+++ b/gfx/gl/shaders/billboardPainter.vert
@@ -0,0 +1,23 @@
+#version 460 core
+
+layout(binding = 1) uniform usampler2DRect materialData;
+
+include(`meshIn.glsl')
+include(`materialDetail.glsl')
+include(`getMaterialDetail.glsl')
+
+out vec3 FragPos;
+out vec2 TexCoords;
+flat out MaterialDetail Material;
+out vec3 Normal;
+out vec4 Colour;
+
+void
+main()
+{
+	TexCoords = texCoord;
+	Material = getMaterialDetail(material);
+	FragPos = position;
+	Colour = colour;
+	Normal = normal;
+}
-- 
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