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Commit af6f7ed8 authored by ztenghui's avatar ztenghui
Browse files

Early rejection on shadows which are outside of the clip bound. 

All the computations are estimated using bounding box.
TODO: Spot shadow could have more accurate but also more expensive methods, we need
more experiments to decide.

Change-Id: I9c10c419576cee55daf0f9f278b0db78cb847447
parent 31dc8f70

libs/hwui/OpenGLRenderer.cpp

+14 −2
Original line number Diff line number Diff line
@@ -3226,11 +3226,13 @@ status_t OpenGLRenderer::drawShadow(const mat4& casterTransformXY, const mat4& c 
    const int casterVertexCount = casterVertices2d.size();

    Vector3 casterPolygon[casterVertexCount];

    float minZ = FLT_MAX;

    float maxZ = -FLT_MAX;

    for (int i = 0; i < casterVertexCount; i++) {

        const Vertex& point2d = casterVertices2d[i];

        casterPolygon[i] = Vector3(point2d.x, point2d.y, 0);

        mapPointFakeZ(casterPolygon[i], casterTransformXY, casterTransformZ);

        minZ = fmin(minZ, casterPolygon[i].z);

        maxZ = fmax(maxZ, casterPolygon[i].z);

    }



    // map the centroid of the caster into 3d
@@ -3248,6 +3250,15 @@ status_t OpenGLRenderer::drawShadow(const mat4& casterTransformXY, const mat4& c 
        }

        centroid3d.z += casterLift;

    }



    // Check whether we want to draw the shadow at all by checking the caster's

    // bounds against clip.

    // We only have ortho projection, so we can just ignore the Z in caster for

    // simple rejection calculation.

    Rect localClip = mSnapshot->getLocalClip();

    Rect casterBounds(casterOutline->getBounds());

    casterTransformXY.mapRect(casterBounds);



    bool isCasterOpaque = (casterAlpha == 1.0f);

    // draw caster's shadows

    if (mCaches.propertyAmbientShadowStrength > 0) {
@@ -3255,7 +3266,7 @@ status_t OpenGLRenderer::drawShadow(const mat4& casterTransformXY, const mat4& c 
        VertexBuffer ambientShadowVertexBuffer;

        VertexBufferMode vertexBufferMode = ShadowTessellator::tessellateAmbientShadow(

                isCasterOpaque, casterPolygon, casterVertexCount, centroid3d,

                ambientShadowVertexBuffer);

                casterBounds, localClip, maxZ, ambientShadowVertexBuffer);

        drawVertexBuffer(vertexBufferMode, ambientShadowVertexBuffer, &paint);

    }
@@ -3266,7 +3277,8 @@ status_t OpenGLRenderer::drawShadow(const mat4& casterTransformXY, const mat4& c 
                mCaches.propertyLightPosYScale, mCaches.propertyLightPosZScale);

        VertexBufferMode vertexBufferMode = ShadowTessellator::tessellateSpotShadow(

                isCasterOpaque, casterPolygon, casterVertexCount, lightPosScale,

                *currentTransform(), getWidth(), getHeight(), spotShadowVertexBuffer);

                *currentTransform(), getWidth(), getHeight(), casterBounds, localClip,

                spotShadowVertexBuffer);

        drawVertexBuffer(vertexBufferMode, spotShadowVertexBuffer, &paint);

    }

libs/hwui/Rect.h

+8 −0
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#define ANDROID_HWUI_RECT_H



#include <cmath>

#include <SkRect.h>



#include <utils/Log.h>
@@ -68,6 +69,13 @@ public: 
            bottom(height) {

    }



    inline Rect(const SkRect& rect):

            left(rect.fLeft),

            top(rect.fTop),

            right(rect.fRight),

            bottom(rect.fBottom) {

    }



    friend int operator==(const Rect& a, const Rect& b) {

        return !memcmp(&a, &b, sizeof(a));

    }

libs/hwui/ShadowTessellator.cpp

+26 −2
Original line number Diff line number Diff line
@@ -35,7 +35,8 @@ static inline T max(T a, T b) { 


VertexBufferMode ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque,

        const Vector3* casterPolygon, int casterVertexCount,

        const Vector3& centroid3d, VertexBuffer& shadowVertexBuffer) {

        const Vector3& centroid3d, const Rect& casterBounds,

        const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer) {

    ATRACE_CALL();



    // A bunch of parameters to tweak the shadow.
@@ -43,6 +44,16 @@ VertexBufferMode ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque, 
    const float heightFactor = 1.0f / 128;

    const float geomFactor = 64;



    Rect ambientShadowBounds(casterBounds);

    ambientShadowBounds.outset(maxZ * geomFactor * heightFactor);



    if (!localClip.intersects(ambientShadowBounds)) {

#if DEBUG_SHADOW

        ALOGD("Ambient shadow is out of clip rect!");

#endif

        return kVertexBufferMode_OnePolyRingShadow;

    }



    return AmbientShadow::createAmbientShadow(isCasterOpaque, casterPolygon,

            casterVertexCount, centroid3d, heightFactor, geomFactor,

            shadowVertexBuffer);
@@ -52,7 +63,8 @@ VertexBufferMode ShadowTessellator::tessellateAmbientShadow(bool isCasterOpaque, 
VertexBufferMode ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque,

        const Vector3* casterPolygon, int casterVertexCount,

        const Vector3& lightPosScale, const mat4& receiverTransform,

        int screenWidth, int screenHeight, VertexBuffer& shadowVertexBuffer) {

        int screenWidth, int screenHeight, const Rect& casterBounds,

        const Rect& localClip, VertexBuffer& shadowVertexBuffer) {

    ATRACE_CALL();



    // A bunch of parameters to tweak the shadow.
@@ -73,6 +85,18 @@ VertexBufferMode ShadowTessellator::tessellateSpotShadow(bool isCasterOpaque, 
    const float lightSize = maximal / 4;

    const int lightVertexCount = 8;



    // Now light and caster are both in local space, we will check whether

    // the shadow is within the clip area.

    Rect lightRect = Rect(lightCenter.x - lightSize, lightCenter.y - lightSize,

            lightCenter.x + lightSize, lightCenter.y + lightSize);

    lightRect.unionWith(localClip);

    if (!lightRect.intersects(casterBounds)) {

#if DEBUG_SHADOW

        ALOGD("Spot shadow is out of clip rect!");

#endif

        return kVertexBufferMode_OnePolyRingShadow;

    }



    VertexBufferMode mode = SpotShadow::createSpotShadow(isCasterOpaque,

            casterPolygon, casterVertexCount, lightCenter, lightSize,

            lightVertexCount, shadowVertexBuffer);

libs/hwui/ShadowTessellator.h

+4 −2
Original line number Diff line number Diff line
@@ -66,12 +66,14 @@ class ShadowTessellator { 
public:

    static VertexBufferMode tessellateAmbientShadow(bool isCasterOpaque,

            const Vector3* casterPolygon, int casterVertexCount,

            const Vector3& centroid3d, VertexBuffer& shadowVertexBuffer);

            const Vector3& centroid3d,  const Rect& casterBounds,

            const Rect& localClip, float maxZ, VertexBuffer& shadowVertexBuffer);



    static VertexBufferMode tessellateSpotShadow(bool isCasterOpaque,

            const Vector3* casterPolygon, int casterVertexCount,

            const Vector3& lightPosScale, const mat4& receiverTransform,

            int screenWidth, int screenHeight, VertexBuffer& shadowVertexBuffer);

            int screenWidth, int screenHeight, const Rect& casterBounds,

            const Rect& localClip, VertexBuffer& shadowVertexBuffer);



    static void generateShadowIndices(uint16_t*  shadowIndices);