Workbench: Shadows

Initial review of the shard shadows in the workbench engine.

Speed optimizations like transform feedback are not implemented yet. I first want this part to be reviewed and merged.

@fclem please check the note in drw_stencil_set it was holding back nequal == 0 as by default DST.stencil_mask was set to 0. questioin is should we remove the whole check or not.

Also I am still looking for a better name (or split the enum) for DRW_STATE_STENCIL_DEPTH_FAIL_INCR_DECR_WRAP

Reviewers: fclem

Reviewed By: fclem

Tags: #code_quest

Differential Revision: https://developer.blender.org/D3198

1 files changed, 23 insertions, 0 deletions

diff --git a/source/blender/draw/engines/workbench/shaders/workbench_shadow_vert.glsl b/source/blender/draw/engines/workbench/shaders/workbench_shadow_vert.glsl
new file mode 100644
index 00000000000..7322266a956
--- /dev/null
+++ b/source/blender/draw/engines/workbench/shaders/workbench_shadow_vert.glsl
@@ -0,0 +1,23 @@
+#define EPSILON 0.000001
+#define INFINITE 100.0
+
+uniform mat4 ModelMatrixInverse;
+uniform mat4 ModelViewProjectionMatrix;
+uniform vec3 lightDirection = vec3(0.57, 0.57, -0.57);
+
+in vec4 pos;
+
+out VertexData {
+	flat vec4 lightDirectionMS;
+	vec4 frontPosition;
+	vec4 backPosition;
+} vertexData;
+
+void main()
+{
+	gl_Position = pos;
+	vertexData.lightDirectionMS = normalize(ModelMatrixInverse * vec4(lightDirection, 0.0));
+	vertexData.lightDirectionMS.w = 0.0;
+	vertexData.frontPosition = ModelViewProjectionMatrix * (pos + vertexData.lightDirectionMS * EPSILON);
+	vertexData.backPosition = ModelViewProjectionMatrix * (pos + vertexData.lightDirectionMS * INFINITE);
+}