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Commit 63d41abb authored by ztenghui's avatar ztenghui
Browse files

Use pre-computed index to draw the shadow. 

Also draw the umbra part as triangle fans instead of zig zag fashion.

b/12840179

Change-Id: Iaa5d15e77351acdd71f076bd8f9bb2d4d2b92faf
parent ef94c6f8

libs/hwui/AmbientShadow.cpp

+35 −105
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include <utils/Vector.h>



#include "AmbientShadow.h"

#include "ShadowTessellator.h"

#include "Vertex.h"



namespace android {
@@ -34,9 +35,7 @@ namespace uirenderer { 
 *                  array.

 * @param vertexCount The length of caster's polygon in terms of number of

 *                    vertices.

 * @param rays The number of rays shooting out from the centroid.

 * @param layers The number of rings outside the polygon.

 * @param strength The darkness of the shadow, the higher, the darker.

 * @param centroid3d The centroid of the shadow caster.

 * @param heightFactor The factor showing the higher the object, the lighter the

 *                     shadow.

 * @param geomFactor The factor scaling the geometry expansion along the normal.
@@ -45,21 +44,18 @@ namespace uirenderer { 
 *               triangle strips mode.

 */

void AmbientShadow::createAmbientShadow(const Vector3* vertices, int vertexCount,

        int rays, int layers, float strength, float heightFactor, float geomFactor,

        const Vector3& centroid3d, float heightFactor, float geomFactor,

        VertexBuffer& shadowVertexBuffer) {



    const int rays = SHADOW_RAY_COUNT;

    const int layers = SHADOW_LAYER_COUNT;

    // Validate the inputs.

    if (strength <= 0 || heightFactor <= 0 || layers <= 0 || rays <= 0

    if (vertexCount < 3 || heightFactor <= 0 || layers <= 0 || rays <= 0

        || geomFactor <= 0) {

#if DEBUG_SHADOW

        ALOGE("Invalid input for createAmbientShadow(), early return!");

#endif

        return;

    }

    int rings = layers + 1;

    int size = rays * rings;

    Vector2 centroid;

    calculatePolygonCentroid(vertices, vertexCount, centroid);



    Vector<Vector2> dir; // TODO: use C++11 unique_ptr

    dir.setCapacity(rays);
@@ -75,7 +71,7 @@ void AmbientShadow::createAmbientShadow(const Vector3* vertices, int vertexCount 
        int edgeIndex;

        float edgeFraction;

        float rayDistance;

        calculateIntersection(vertices, vertexCount, centroid, dir[i], edgeIndex,

        calculateIntersection(vertices, vertexCount, centroid3d, dir[i], edgeIndex,

                edgeFraction, rayDistance);

        rayDist[i] = rayDistance;

        if (edgeIndex < 0 || edgeIndex >= vertexCount) {
@@ -91,8 +87,7 @@ void AmbientShadow::createAmbientShadow(const Vector3* vertices, int vertexCount 


    // The output buffer length basically is roughly rays * layers, but since we

    // need triangle strips, so we need to duplicate vertices to accomplish that.

    const int shadowVertexCount = (2 + rays + ((layers) * 2 * (rays + 1)));

    AlphaVertex* shadowVertices = shadowVertexBuffer.alloc<AlphaVertex>(shadowVertexCount);

    AlphaVertex* shadowVertices = shadowVertexBuffer.alloc<AlphaVertex>(SHADOW_VERTEX_COUNT);



    // Calculate the vertex of the shadows.

    //
@@ -101,110 +96,45 @@ void AmbientShadow::createAmbientShadow(const Vector3* vertices, int vertexCount 
    // calculate the normal N, which should be perpendicular to the edge of the

    // polygon (represented by the neighbor intersection points) .

    // Shadow's vertices will be generated as : P + N * scale.

    int currentIndex = 0;

    for (int r = 0; r < layers; r++) {

        int firstInLayer = currentIndex;

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

    int currentVertexIndex = 0;

    for (int layerIndex = 0; layerIndex <= layers; layerIndex++) {

        for (int rayIndex = 0; rayIndex < rays; rayIndex++) {



            Vector2 normal(1.0f, 0.0f);

            calculateNormal(rays, i, dir.array(), rayDist, normal);

            calculateNormal(rays, rayIndex, dir.array(), rayDist, normal);



            float opacity = strength * (0.5f) / (1 + rayHeight[i] / heightFactor);

            float opacity = 1.0 / (1 + rayHeight[rayIndex] / heightFactor);



            // The vertex should be start from rayDist[i] then scale the

            // normalizeNormal!

            Vector2 intersection = dir[i] * rayDist[i] + centroid;



            // Use 2 rings' vertices to complete one layer's strip

            for (int j = r; j < (r + 2); j++) {

                float jf = j / (float)(rings - 1);



                float expansionDist = rayHeight[i] / heightFactor * geomFactor * jf;

                AlphaVertex::set(&shadowVertices[currentIndex],

            Vector2 intersection = dir[rayIndex] * rayDist[rayIndex] +

                    Vector2(centroid3d.x, centroid3d.y);



            float layerRatio = layerIndex / (float)(layers);

            // The higher the intersection is, the further the ambient shadow expanded.

            float expansionDist = rayHeight[rayIndex] / heightFactor *

                    geomFactor * (1 - layerRatio);

            AlphaVertex::set(&shadowVertices[currentVertexIndex++],

                    intersection.x + normal.x * expansionDist,

                    intersection.y + normal.y * expansionDist,

                        (1 - jf) * opacity);

                currentIndex++;

            }

                    layerRatio * opacity);

        }



        // From one layer to the next, we need to duplicate the vertex to

        // continue as a single strip.

        shadowVertices[currentIndex] = shadowVertices[firstInLayer];

        currentIndex++;

        shadowVertices[currentIndex] = shadowVertices[firstInLayer + 1];

        currentIndex++;

    }

    float centroidAlpha = 1.0 / (1 + centroid3d.z / heightFactor);

    AlphaVertex::set(&shadowVertices[currentVertexIndex++],

            centroid3d.x, centroid3d.y, centroidAlpha);



    // After all rings are done, we need to jump into the polygon.

    // In order to keep everything in a strip, we need to duplicate the last one

    // of the rings and the first one inside the polygon.

    int lastInRings = currentIndex - 1;

    shadowVertices[currentIndex] = shadowVertices[lastInRings];

    currentIndex++;



    // We skip one and fill it back after we finish the internal triangles.

    currentIndex++;

    int firstInternal = currentIndex;



    // Combine the internal area of the polygon into a triangle strip, too.

    // The basic idea is zig zag between the intersection points.

    // 0 -> (n - 1) -> 1 -> (n - 2) ...

    for (int k = 0; k < rays; k++) {

        int  i = k / 2;

        if ((k & 1) == 1) { // traverse the inside in a zig zag pattern for strips

            i = rays - i - 1;

        }

        float cast = rayDist[i] * (1 + rayHeight[i] / heightFactor);

        float opacity = strength * (0.5f) / (1 + rayHeight[i] / heightFactor);

        float t = rayDist[i];



        AlphaVertex::set(&shadowVertices[currentIndex], dir[i].x * t + centroid.x,

                dir[i].y * t + centroid.y, opacity);

        currentIndex++;

    }



    currentIndex = firstInternal - 1;

    shadowVertices[currentIndex] = shadowVertices[firstInternal];

#if DEBUG_SHADOW

    if (currentVertexIndex != SHADOW_VERTEX_COUNT) {

        ALOGE("number of vertex generated for ambient shadow is wrong! "

              "current: %d , expected: %d", currentVertexIndex, SHADOW_VERTEX_COUNT);

    }



/**

 * Calculate the centroid of a given polygon.

 *

 * @param vertices The shadow caster's polygon, which is represented in a

 *                 straight Vector3 array.

 * @param vertexCount The length of caster's polygon in terms of number of vertices.

 *

 * @param centroid Return the centroid of the polygon.

 */

void AmbientShadow::calculatePolygonCentroid(const Vector3* vertices, int vertexCount,

        Vector2& centroid) {

    float sumx = 0;

    float sumy = 0;

    int p1 = vertexCount - 1;

    float area = 0;

    for (int p2 = 0; p2 < vertexCount; p2++) {

        float x1 = vertices[p1].x;

        float y1 = vertices[p1].y;

        float x2 = vertices[p2].x;

        float y2 = vertices[p2].y;

        float a = (x1 * y2 - x2 * y1);

        sumx += (x1 + x2) * a;

        sumy += (y1 + y2) * a;

        area += a;

        p1 = p2;

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

        ALOGD("ambient shadow value: i %d, (x:%f, y:%f, a:%f)", i, shadowVertices[i].x,

                shadowVertices[i].y, shadowVertices[i].alpha);

    }



    if (area == 0) {

#if DEBUG_SHADOW

        ALOGE("Area is 0!");

#endif

        centroid.x = vertices[0].x;

        centroid.y = vertices[0].y;

    } else {

        centroid.x = sumx / (3 * area);

        centroid.y = sumy / (3 * area);

    }

}



/**
@@ -238,7 +168,7 @@ void AmbientShadow::calculateRayDirections(int rays, Vector2* dir) { 
 * @param outRayDist Return the ray distance from centroid to the intersection.

 */

void AmbientShadow::calculateIntersection(const Vector3* vertices, int vertexCount,

        const Vector2& start, const Vector2& dir, int& outEdgeIndex,

        const Vector3& start, const Vector2& dir, int& outEdgeIndex,

        float& outEdgeFraction, float& outRayDist) {

    float startX = start.x;

    float startY = start.y;

libs/hwui/AmbientShadow.h

+3 −5
Original line number Diff line number Diff line
@@ -34,17 +34,15 @@ namespace uirenderer { 
 */

class AmbientShadow {

public:

    static void createAmbientShadow(const Vector3* poly, int polyLength, int rays,

            int layers, float strength, float heightFactor, float geomFactor,

    static void createAmbientShadow(const Vector3* poly, int polyLength,

            const Vector3& centroid3d, float heightFactor, float geomFactor,

            VertexBuffer& shadowVertexBuffer);



private:

    static void calculatePolygonCentroid(const Vector3* poly, int len, Vector2& centroid);



    static void calculateRayDirections(int rays, Vector2* dir);



    static void calculateIntersection(const Vector3* poly, int nbVertices,

            const Vector2& start, const Vector2& dir, int& outEdgeIndex,

            const Vector3& start, const Vector2& dir, int& outEdgeIndex,

            float& outEdgeFraction, float& outRayDist);



    static void calculateNormal(int rays, int currentRayIndex, const Vector2* dir,

libs/hwui/Caches.cpp

+25 −5
Original line number Diff line number Diff line
@@ -23,6 +23,7 @@ 
#include "DisplayListRenderer.h"

#include "Properties.h"

#include "LayerRenderer.h"

#include "ShadowTessellator.h"



namespace android {
@@ -86,7 +87,7 @@ bool Caches::init() { 


    mRegionMesh = NULL;

    mMeshIndices = 0;



    mShadowStripsIndices = 0;

    blend = false;

    lastSrcMode = GL_ZERO;

    lastDstMode = GL_ZERO;
@@ -223,6 +224,9 @@ void Caches::terminate() { 
    mMeshIndices = 0;

    mRegionMesh = NULL;



    glDeleteBuffers(1, &mShadowStripsIndices);

    mShadowStripsIndices = 0;



    fboCache.clear();



    programCache.clear();
@@ -404,7 +408,7 @@ bool Caches::unbindMeshBuffer() { 
    return false;

}



bool Caches::bindIndicesBuffer(const GLuint buffer) {

bool Caches::bindIndicesBufferInternal(const GLuint buffer) {

    if (mCurrentIndicesBuffer != buffer) {

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);

        mCurrentIndicesBuffer = buffer;
@@ -413,7 +417,7 @@ bool Caches::bindIndicesBuffer(const GLuint buffer) { 
    return false;

}



bool Caches::bindIndicesBuffer() {

bool Caches::bindQuadIndicesBuffer() {

    if (!mMeshIndices) {

        uint16_t* regionIndices = new uint16_t[gMaxNumberOfQuads * 6];

        for (uint32_t i = 0; i < gMaxNumberOfQuads; i++) {
@@ -428,7 +432,7 @@ bool Caches::bindIndicesBuffer() { 
        }



        glGenBuffers(1, &mMeshIndices);

        bool force = bindIndicesBuffer(mMeshIndices);

        bool force = bindIndicesBufferInternal(mMeshIndices);

        glBufferData(GL_ELEMENT_ARRAY_BUFFER, gMaxNumberOfQuads * 6 * sizeof(uint16_t),

                regionIndices, GL_STATIC_DRAW);
@@ -436,7 +440,23 @@ bool Caches::bindIndicesBuffer() { 
        return force;

    }



    return bindIndicesBuffer(mMeshIndices);

    return bindIndicesBufferInternal(mMeshIndices);

}



bool Caches::bindShadowIndicesBuffer() {

    if (!mShadowStripsIndices) {

        uint16_t* shadowIndices = new uint16_t[SHADOW_INDEX_COUNT];

        ShadowTessellator::generateShadowIndices(shadowIndices);

        glGenBuffers(1, &mShadowStripsIndices);

        bool force = bindIndicesBufferInternal(mShadowStripsIndices);

        glBufferData(GL_ELEMENT_ARRAY_BUFFER, SHADOW_INDEX_COUNT * sizeof(uint16_t),

            shadowIndices, GL_STATIC_DRAW);



        delete[] shadowIndices;

        return force;

    }



    return bindIndicesBufferInternal(mShadowStripsIndices);

}



bool Caches::unbindIndicesBuffer() {

libs/hwui/Caches.h

+5 −2
Original line number Diff line number Diff line
@@ -190,8 +190,8 @@ public: 
     * Binds a global indices buffer that can draw up to

     * gMaxNumberOfQuads quads.

     */

    bool bindIndicesBuffer();

    bool bindIndicesBuffer(const GLuint buffer);

    bool bindQuadIndicesBuffer();

    bool bindShadowIndicesBuffer();

    bool unbindIndicesBuffer();



    /**
@@ -381,6 +381,8 @@ private: 
    void initConstraints();

    void initStaticProperties();



    bool bindIndicesBufferInternal(const GLuint buffer);



    static void eventMarkNull(GLsizei length, const GLchar* marker) { }

    static void startMarkNull(GLsizei length, const GLchar* marker) { }

    static void endMarkNull() { }
@@ -417,6 +419,7 @@ private: 


    // Global index buffer

    GLuint mMeshIndices;

    GLuint mShadowStripsIndices;



    mutable Mutex mGarbageLock;

    Vector<Layer*> mLayerGarbage;

libs/hwui/FontRenderer.cpp

+1 −1
Original line number Diff line number Diff line
@@ -498,7 +498,7 @@ void FontRenderer::issueDrawCommand(Vector<CacheTexture*>& cacheTextures) { 
                }



                checkTextureUpdate();

                caches.bindIndicesBuffer();

                caches.bindQuadIndicesBuffer();



                if (!mDrawn) {

                    // If returns true, a VBO was bound and we must