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Commit 06e9f324 authored by Arun's avatar Arun Committed by Chris Craik
Browse files

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
parent 142a392b

libs/hwui/ProgramCache.cpp

+18 −13
Original line number Diff line number Diff line
@@ -58,7 +58,9 @@ const char* gVS_Header_Uniforms_HasBitmap = 
        "uniform mat4 textureTransform;\n"

        "uniform mediump vec2 textureDimension;\n";

const char* gVS_Header_Uniforms_HasRoundRectClip =

        "uniform mat4 roundRectInvTransform;\n";

        "uniform mat4 roundRectInvTransform;\n"

        "uniform mediump vec4 roundRectInnerRectLTWH;\n"

        "uniform mediump float roundRectRadius;\n";

const char* gVS_Header_Varyings_HasTexture =

        "varying vec2 outTexCoords;\n";

const char* gVS_Header_Varyings_HasColors =
@@ -87,7 +89,7 @@ const char* gVS_Header_Varyings_HasGradient[6] = { 
        "varying vec2 ditherTexCoords;\n",

};

const char* gVS_Header_Varyings_HasRoundRectClip =

        "varying highp vec2 roundRectPos;\n";

        "varying mediump vec2 roundRectPos;\n";

const char* gVS_Main =

        "\nvoid main(void) {\n";

const char* gVS_Main_OutTexCoords =
@@ -125,7 +127,7 @@ const char* gVS_Main_VertexAlpha = 
        "    alpha = vtxAlpha;\n";



const char* gVS_Main_HasRoundRectClip =

        "    roundRectPos = (roundRectInvTransform * transformedPosition).xy;\n";

        "    roundRectPos = ((roundRectInvTransform * transformedPosition).xy / roundRectRadius) - roundRectInnerRectLTWH.xy;\n";

const char* gVS_Footer =

        "}\n\n";
@@ -169,8 +171,8 @@ const char* gFS_Uniforms_ColorOp[3] = { 
};



const char* gFS_Uniforms_HasRoundRectClip =

        "uniform vec4 roundRectInnerRectLTRB;\n"

        "uniform float roundRectRadius;\n";

        "uniform mediump vec4 roundRectInnerRectLTWH;\n"

        "uniform mediump float roundRectRadius;\n";



const char* gFS_Main =

        "\nvoid main(void) {\n"
@@ -315,15 +317,18 @@ const char* gFS_Main_ApplyColorOp[3] = { 
        "    fragColor = blendColors(colorBlend, fragColor);\n"

};



// Note: LTRB -> xyzw

// Note: LTWH (left top width height) -> xyzw

// roundRectPos is now divided by roundRectRadius in vertex shader

// after we also subtract roundRectInnerRectLTWH.xy from roundRectPos

const char* gFS_Main_FragColor_HasRoundRectClip =

        "    mediump vec2 fragToLT = roundRectInnerRectLTRB.xy - roundRectPos;\n"

        "    mediump vec2 fragFromRB = roundRectPos - roundRectInnerRectLTRB.zw;\n"



        // divide + multiply by 128 to avoid falling out of range in length() function

        "    mediump vec2 dist = max(max(fragToLT, fragFromRB), vec2(0.0, 0.0)) / 128.0;\n"

        "    mediump float linearDist = roundRectRadius - (length(dist) * 128.0);\n"

        "    gl_FragColor *= clamp(linearDist, 0.0, 1.0);\n";

        "    mediump vec2 fragToLT = -roundRectPos;\n"

        "    mediump vec2 fragFromRB = roundRectPos - roundRectInnerRectLTWH.zw;\n"



        // since distance is divided by radius, it's in [0;1] so precision is not an issue

        // this also lets us clamp(0.0, 1.0) instead of max() which is cheaper on GPUs

        "    mediump vec2 dist = clamp(max(fragToLT, fragFromRB), 0.0, 1.0);\n"

        "    mediump float linearDist = clamp(roundRectRadius - (length(dist) * roundRectRadius), 0.0, 1.0);\n"

        "    gl_FragColor *= linearDist;\n";



const char* gFS_Main_DebugHighlight =

        "    gl_FragColor.rgb = vec3(0.0, gl_FragColor.a, 0.0);\n";

libs/hwui/renderstate/RenderState.cpp

+11 −5
Original line number Diff line number Diff line
@@ -274,14 +274,20 @@ void RenderState::render(const Glop& glop, const Matrix4& orthoMatrix) { 
        // 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);

    }