Optimised hwui rounded corners shader
This is a ~2x performance increase for the rounded corners shader which
was previously shader limited even on many high-end GPUs. It simplifies
the calculations by pre-dividing by the radius, which also allows to
maintain mediump/FP16 precision (this improves performance and might
improve image quality on GPUs that don't support highp e.g. Mali-400).
It also uses a conditional in the shader to save much of the work on
the vast majority of pixels which are not close to the corners.
Test: manual - visual inspection on fugu (nexus player)
Change-Id: I38f491cfb006e2991ef0b9d6b3d67d2c4d328d44
diff --git a/libs/hwui/renderstate/RenderState.cpp b/libs/hwui/renderstate/RenderState.cpp
index c4e8e4f..2a3a9f3 100644
--- a/libs/hwui/renderstate/RenderState.cpp
+++ b/libs/hwui/renderstate/RenderState.cpp
@@ -274,14 +274,20 @@
// TODO: avoid query, and cache values (or RRCS ptr) in program
const RoundRectClipState* state = glop.roundRectClipState;
const Rect& innerRect = state->innerRect;
- glUniform4f(fill.program->getUniform("roundRectInnerRectLTRB"),
- innerRect.left, innerRect.top,
- innerRect.right, innerRect.bottom);
- glUniformMatrix4fv(fill.program->getUniform("roundRectInvTransform"),
- 1, GL_FALSE, &state->matrix.data[0]);
// add half pixel to round out integer rect space to cover pixel centers
float roundedOutRadius = state->radius + 0.5f;
+
+ // Divide by the radius to simplify the calculations in the fragment shader
+ // roundRectPos is also passed from vertex shader relative to top/left & radius
+ glUniform4f(fill.program->getUniform("roundRectInnerRectLTWH"),
+ innerRect.left / roundedOutRadius, innerRect.top / roundedOutRadius,
+ (innerRect.right - innerRect.left) / roundedOutRadius,
+ (innerRect.bottom - innerRect.top) / roundedOutRadius);
+
+ glUniformMatrix4fv(fill.program->getUniform("roundRectInvTransform"),
+ 1, GL_FALSE, &state->matrix.data[0]);
+
glUniform1f(fill.program->getUniform("roundRectRadius"),
roundedOutRadius);
}