added support for PLS path rendering

src/gpu/gl/GrGLGpu.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #include "GrGLGpu.h"
 #include "GrGLGLSL.h"
 #include "GrGLStencilAttachment.h"
 #include "GrGLTextureRenderTarget.h"
 #include "GrGpuResourcePriv.h"
 #include "GrPipeline.h"
+#include "GrPLSGeometryProcessor.h"
 #include "GrRenderTargetPriv.h"
 #include "GrSurfacePriv.h"
 #include "GrTexturePriv.h"
 #include "GrTypes.h"
 #include "GrVertices.h"
 #include "builders/GrGLShaderStringBuilder.h"
 #include "glsl/GrGLSL.h"
 #include "glsl/GrGLSLCaps.h"
+#include "glsl/GrGLSLPLSPathRendering.h"
 #include "SkStrokeRec.h"
 #include "SkTemplates.h"
 
 #define GL_CALL(X) GR_GL_CALL(this->glInterface(), X)
 #define GL_CALL_RET(RET, X) GR_GL_CALL_RET(this->glInterface(), RET, X)
 
 #define SKIP_CACHE_CHECK    true
 
 #if GR_GL_CHECK_ALLOC_WITH_GET_ERROR
     #define CLEAR_ERROR_BEFORE_ALLOC(iface)   GrGLClearErr(iface)
     #define GL_ALLOC_CALL(iface, call)        GR_GL_CALL_NOERRCHECK(iface, call)
     #define CHECK_ALLOC_ERROR(iface)          GR_GL_GET_ERROR(iface)
 #else
     #define CLEAR_ERROR_BEFORE_ALLOC(iface)
     #define GL_ALLOC_CALL(iface, call)        GR_GL_CALL(iface, call)
     #define CHECK_ALLOC_ERROR(iface)          GR_GL_NO_ERROR
 #endif
 
+#define GL_SHADER_PIXEL_LOCAL_STORAGE_EXT 0x8F64

[bsalomon, 2016/01/13 19:15:34]

GrGLDefines.h

+
 
 ///////////////////////////////////////////////////////////////////////////////
 
 
 static const GrGLenum gXfermodeEquation2Blend[] = {
     // Basic OpenGL blend equations.
     GR_GL_FUNC_ADD,
     GR_GL_FUNC_SUBTRACT,
     GR_GL_FUNC_REVERSE_SUBTRACT,
 
@@ skipping 166 matching lines @@
     fTempSrcFBOID = 0;
     fTempDstFBOID = 0;
     fStencilClearFBOID = 0;
 
     if (this->glCaps().shaderCaps()->pathRenderingSupport()) {
         fPathRendering.reset(new GrGLPathRendering(this));
     }
     this->createCopyPrograms();
     fWireRectProgram.fProgram = 0;
     fWireRectArrayBuffer = 0;
+    #ifdef ENABLE_PLS

[bsalomon, 2016/01/13 19:15:34]

untab

+        if (this->glCaps().shaderCaps()->pixelLocalStorageSize() > 0) {

[bsalomon, 2016/01/13 19:15:34]

Check for framebuffer_fetch too?

+            this->createPLSSetupProgram();
+        }
+        else {
+            memset(&fPLSSetupProgram, 0, sizeof(fPLSSetupProgram));
+        }
+        fHWPLSEnabled = false;
+    #endif
 }
 
 GrGLGpu::~GrGLGpu() {
     if (0 != fHWProgramID) {
         // detach the current program so there is no confusion on OpenGL's part
         // that we want it to be deleted
         GL_CALL(UseProgram(0));
     }
 
     if (0 != fTempSrcFBOID) {
@@ skipping 17 matching lines @@
     }
 
     if (0 != fWireRectProgram.fProgram) {
         GL_CALL(DeleteProgram(fWireRectProgram.fProgram));
     }
 
     if (0 != fWireRectArrayBuffer) {
         GL_CALL(DeleteBuffers(1, &fWireRectArrayBuffer));
     }
 
+    #ifdef ENABLE_PLS
+        if (0 != fPLSSetupProgram.fArrayBuffer) {
+            GL_CALL(DeleteBuffers(1, &fPLSSetupProgram.fArrayBuffer));
+        }
+
+        if (0 != fPLSSetupProgram.fProgram) {
+            GL_CALL(DeleteProgram(fPLSSetupProgram.fProgram));
+        }
+    #endif
+
     delete fProgramCache;
 }
 
+#ifdef ENABLE_PLS

[bsalomon, 2016/01/13 19:15:34]

Any code that won't be run without the GrPLSPR subclass being installed need not
be protected by the macro. Probably better that it isn't so that it fail to
compile due to changes in later CLs.

You could make the macro just toggle whether GrGLCaps::pixelLocalStorageSize()
always returns zero, and leave everything else in a default build.

+void GrGLGpu::createPLSSetupProgram() {
+    const char* version = this->glCaps().glslCaps()->versionDeclString();
+
+    GrGLSLShaderVar aVertex("a_vertex", kVec2f_GrSLType, GrShaderVar::kAttribute_TypeModifier);
+    GrGLSLShaderVar uTexCoordXform("u_texCoordXform", kVec4f_GrSLType,
+                                   GrShaderVar::kUniform_TypeModifier);
+    GrGLSLShaderVar uPosXform("u_posXform", kVec4f_GrSLType, GrShaderVar::kUniform_TypeModifier);
+    GrGLSLShaderVar uTexture("u_texture", kSampler2D_GrSLType, GrShaderVar::kUniform_TypeModifier);
+    GrGLSLShaderVar vTexCoord("v_texCoord", kVec2f_GrSLType, GrShaderVar::kVaryingOut_TypeModifier);
+    
+    SkString vshaderTxt(version);
+    aVertex.appendDecl(this->glCaps().glslCaps(), &vshaderTxt);
+    vshaderTxt.append(";");
+    uTexCoordXform.appendDecl(this->glCaps().glslCaps(), &vshaderTxt);
+    vshaderTxt.append(";");
+    uPosXform.appendDecl(this->glCaps().glslCaps(), &vshaderTxt);
+    vshaderTxt.append(";");
+    vTexCoord.appendDecl(this->glCaps().glslCaps(), &vshaderTxt);
+    vshaderTxt.append(";");
+    
+    vshaderTxt.append(
+        "// PLS Setup Program VS\n"
+        "void main() {"
+        "  gl_Position.xy = a_vertex * u_posXform.xy + u_posXform.zw;"
+        "  gl_Position.zw = vec2(0, 1);"
+        "}"
+    );
+
+    SkString fshaderTxt(version);
+    fshaderTxt.append("#extension GL_ARM_shader_framebuffer_fetch : require\n");

[bsalomon, 2016/01/13 19:15:34]

This extension has aliases, see GrGLSLCaps()::fbFetchExtensionString()

+    fshaderTxt.append("#extension GL_EXT_shader_pixel_local_storage : require\n");
+    GrGLSLAppendDefaultFloatPrecisionDeclaration(kDefault_GrSLPrecision,
+                                                 *this->glCaps().glslCaps(),
+                                                 &fshaderTxt);
+    vTexCoord.setTypeModifier(GrShaderVar::kVaryingIn_TypeModifier);
+    vTexCoord.appendDecl(this->glCaps().glslCaps(), &fshaderTxt);
+    fshaderTxt.append(";");
+    uTexture.appendDecl(this->glCaps().glslCaps(), &fshaderTxt);
+    fshaderTxt.append(";");
+
+    fshaderTxt.appendf(
+        "// PLS Setup Program FS\n"
+        PLS_PATH_DATA_DECL
+        "void main() {\n"
+        "    " PLS_DSTCOLOR_NAME " = gl_LastFragColorARM;\n"
+        "    pls.windings = ivec4(0, 0, 0, 0);\n"
+        "}"
+    );
+    GL_CALL_RET(fPLSSetupProgram.fProgram, CreateProgram());
+    const char* str;
+    GrGLint length;
+
+    str = vshaderTxt.c_str();
+    length = SkToInt(vshaderTxt.size());
+    GrGLuint vshader = GrGLCompileAndAttachShader(*fGLContext, fPLSSetupProgram.fProgram,
+                                                  GR_GL_VERTEX_SHADER, &str, &length, 1, &fStats);
+
+    str = fshaderTxt.c_str();
+    length = SkToInt(fshaderTxt.size());
+    GrGLuint fshader = GrGLCompileAndAttachShader(*fGLContext, fPLSSetupProgram.fProgram,
+                                                  GR_GL_FRAGMENT_SHADER, &str, &length, 1, &fStats);
+
+    GL_CALL(LinkProgram(fPLSSetupProgram.fProgram));
+
+    GL_CALL_RET(fPLSSetupProgram.fPosXformUniform, GetUniformLocation(fPLSSetupProgram.fProgram,
+                                                                  "u_posXform"));
+
+    GL_CALL(BindAttribLocation(fPLSSetupProgram.fProgram, 0, "a_vertex"));
+
+    GL_CALL(DeleteShader(vshader));
+    GL_CALL(DeleteShader(fshader));
+
+    GL_CALL(GenBuffers(1, &fPLSSetupProgram.fArrayBuffer));
+    fHWGeometryState.setVertexBufferID(this, fPLSSetupProgram.fArrayBuffer);
+    static const GrGLfloat vdata[] = {
+        0, 0,
+        0, 1,
+        1, 0,
+        1, 1
+    };
+    GL_ALLOC_CALL(this->glInterface(),
+                  BufferData(GR_GL_ARRAY_BUFFER,
+                             (GrGLsizeiptr) sizeof(vdata),
+                             vdata,  // data ptr
+                             GR_GL_STATIC_DRAW));
+}
+#endif
+
 void GrGLGpu::contextAbandoned() {
     INHERITED::contextAbandoned();
     fProgramCache->abandon();
     fHWProgramID = 0;
     fTempSrcFBOID = 0;
     fTempDstFBOID = 0;
     fStencilClearFBOID = 0;
     fCopyProgramArrayBuffer = 0;
     for (size_t i = 0; i < SK_ARRAY_COUNT(fCopyPrograms); ++i) {
         fCopyPrograms[i].fProgram = 0;
@@ skipping 1849 matching lines @@
             if (!flipY) {
                 dst += rowBytes;
             } else {
                 dst -= rowBytes;
             }
         }
     }
     return true;
 }
 
+void GrGLGpu::performFlushWorkaround() {
+    #ifdef ENABLE_PLS
+        if (this->glCaps().shaderCaps()->pixelLocalStorageSize() > 0) {
+            /* There is an ARM driver bug where if we use PLS, and then draw a frame which does not 
+             * use PLS, it leaves garbage all over the place. As a workaround, we use PLS in a 
+             * trivial way every frame. 
+             */
+            if (kYes_TriState == fHWScissorSettings.fEnabled) {
+                GL_CALL(Disable(GR_GL_SCISSOR_TEST));
+            }
+            GL_CALL(Enable(GL_SHADER_PIXEL_LOCAL_STORAGE_EXT));
+            this->stampRectUsingProgram(fPLSSetupProgram.fProgram, 
+                                        SkRect::MakeXYWH(-100.0f, -100.0f, 0.01f, 0.01f), 
+                                        fPLSSetupProgram.fPosXformUniform, 
+                                        fPLSSetupProgram.fArrayBuffer);
+            GL_CALL(Disable(GL_SHADER_PIXEL_LOCAL_STORAGE_EXT));
+            if (kYes_TriState == fHWScissorSettings.fEnabled) {
+                GL_CALL(Enable(GR_GL_SCISSOR_TEST));
+            }
+        }
+    #endif
+}
+
 void GrGLGpu::flushRenderTarget(GrGLRenderTarget* target, const SkIRect* bound) {
-
     SkASSERT(target);
 
     uint32_t rtID = target->getUniqueID();
     if (fHWBoundRenderTargetUniqueID != rtID) {
         fStats.incRenderTargetBinds();
         GL_CALL(BindFramebuffer(GR_GL_FRAMEBUFFER, target->renderFBOID()));
 #ifdef SK_DEBUG
         // don't do this check in Chromium -- this is causing
         // lots of repeated command buffer flushes when the compositor is
         // rendering with Ganesh, which is really slow; even too slow for
@@ skipping 62 matching lines @@
             }
          }
     #endif
 #endif
 
 void GrGLGpu::onDraw(const DrawArgs& args, const GrNonInstancedVertices& vertices) {
     if (!this->flushGLState(args)) {
         return;
     }
 
+    #ifdef ENABLE_PLS
+        GrPixelLocalStorageState plsState = args.fPrimitiveProcessor->getPixelLocalStorageState();
+        if (!fHWPLSEnabled && plsState != GrPixelLocalStorageState::kDisabled_State) {
+            GL_CALL(Enable(GL_SHADER_PIXEL_LOCAL_STORAGE_EXT));
+            this->setupPixelLocalStorage(args);
+            fHWPLSEnabled = true;
+        }
+        if (plsState == GrPixelLocalStorageState::kFinish_State) {
+            GrStencilSettings stencil;
+            stencil.setDisabled();
+            this->flushStencil(stencil);
+        }
+    #endif
+
     size_t indexOffsetInBytes = 0;
     this->setupGeometry(*args.fPrimitiveProcessor, vertices, &indexOffsetInBytes);
 
     SkASSERT((size_t)vertices.primitiveType() < SK_ARRAY_COUNT(gPrimitiveType2GLMode));
 
     if (vertices.isIndexed()) {
         GrGLvoid* indices =
             reinterpret_cast<GrGLvoid*>(indexOffsetInBytes + sizeof(uint16_t) *
                                         vertices.startIndex());
         // info.startVertex() was accounted for by setupGeometry.
         GL_CALL(DrawElements(gPrimitiveType2GLMode[vertices.primitiveType()],
                              vertices.indexCount(),
                              GR_GL_UNSIGNED_SHORT,
                              indices));
     } else {
         // Pass 0 for parameter first. We have to adjust glVertexAttribPointer() to account for
         // startVertex in the DrawElements case. So we always rely on setupGeometry to have
         // accounted for startVertex.
         GL_CALL(DrawArrays(gPrimitiveType2GLMode[vertices.primitiveType()], 0,
                            vertices.vertexCount()));
     }
+
+    #ifdef ENABLE_PLS
+        if (fHWPLSEnabled && plsState == GrPixelLocalStorageState::kFinish_State) {
+            // PLS draws always involve multiple draws, finishing up with a non-PLS
+            // draw that writes to the color buffer. That draw ends up here; we wait
+            // until after it is complete to actually disable PLS.
+            GL_CALL(Disable(GL_SHADER_PIXEL_LOCAL_STORAGE_EXT));
+            fHWPLSEnabled = false;
+            this->disableScissor();
+        }
+    #endif
+
 #if SWAP_PER_DRAW
     glFlush();
     #if defined(SK_BUILD_FOR_MAC)
         aglSwapBuffers(aglGetCurrentContext());
         int set_a_break_pt_here = 9;
         aglSwapBuffers(aglGetCurrentContext());
     #elif defined(SK_BUILD_FOR_WIN32)
         SwapBuf();
         int set_a_break_pt_here = 9;
         SwapBuf();
     #endif
 #endif
 }
 
+void GrGLGpu::stampRectUsingProgram(GrGLuint program, const SkRect& bounds, GrGLint posXformUniform, 
+                                    GrGLuint arrayBuffer) {
+    GL_CALL(UseProgram(program));
+    this->fHWGeometryState.setVertexArrayID(this, 0);
+
+    GrGLAttribArrayState* attribs =
+            this->fHWGeometryState.bindArrayAndBufferToDraw(this, arrayBuffer);
+    attribs->set(this, 0, arrayBuffer, 2, GR_GL_FLOAT, false, 2 * sizeof(GrGLfloat), 0);
+    attribs->disableUnusedArrays(this, 0x1);
+
+    GL_CALL(Uniform4f(posXformUniform, bounds.width(), bounds.height(), bounds.left(), 
+                      bounds.top()));
+
+    GrXferProcessor::BlendInfo blendInfo;
+    blendInfo.reset();
+    this->flushBlend(blendInfo, GrSwizzle());
+    this->flushColorWrite(true);
+    this->flushDrawFace(GrPipelineBuilder::kBoth_DrawFace);
+    if (!fHWStencilSettings.isDisabled()) {
+        GL_CALL(Disable(GR_GL_STENCIL_TEST));
+    }
+    GL_CALL(DrawArrays(GR_GL_TRIANGLE_STRIP, 0, 4));
+    GL_CALL(UseProgram(fHWProgramID));
+    if (!fHWStencilSettings.isDisabled()) {
+        GL_CALL(Enable(GR_GL_STENCIL_TEST));
+    }
+}
+
+#ifdef ENABLE_PLS
+void GrGLGpu::setupPixelLocalStorage(const DrawArgs& args) {
+    const SkRect& bounds = 
+            static_cast<const GrPLSGeometryProcessor*>(args.fPrimitiveProcessor)->fBounds;
+    // setup pixel local storage -- this means capturing and storing the current framebuffer color
+    // and initializing the winding counts to zero
+    GrRenderTarget* rt = args.fPipeline->getRenderTarget();
+    SkScalar width = rt->width();
+    SkScalar height = rt->height();
+    // dst rect edges in NDC (-1 to 1)
+    // having some issues with rounding, just expand the bounds by 1 and trust the scissor to keep
+    // it contained properly
+    GrGLfloat dx0 = 2.0f * (bounds.left() - 1) / width - 1.0f;
+    GrGLfloat dx1 = 2.0f * (bounds.right() + 1) / width - 1.0f;
+    GrGLfloat dy0 = -2.0f * (bounds.top() - 1) / height + 1.0f;
+    GrGLfloat dy1 = -2.0f * (bounds.bottom() + 1) / height + 1.0f;
+    SkRect deviceBounds = SkRect::MakeXYWH(dx0, dy0, dx1 - dx0, dy1 - dy0);
+    
+    GL_CALL(Enable(GR_GL_FETCH_PER_SAMPLE_ARM));
+    this->stampRectUsingProgram(fPLSSetupProgram.fProgram, deviceBounds, 
+                                fPLSSetupProgram.fPosXformUniform, fPLSSetupProgram.fArrayBuffer);
+}
+#endif
+
 void GrGLGpu::onResolveRenderTarget(GrRenderTarget* target) {
     GrGLRenderTarget* rt = static_cast<GrGLRenderTarget*>(target);
     if (rt->needsResolve()) {
         // Some extensions automatically resolves the texture when it is read.
         if (this->glCaps().usesMSAARenderBuffers()) {
             SkASSERT(rt->textureFBOID() != rt->renderFBOID());
             fStats.incRenderTargetBinds();
             fStats.incRenderTargetBinds();
             GL_CALL(BindFramebuffer(GR_GL_READ_FRAMEBUFFER, rt->renderFBOID()));
             GL_CALL(BindFramebuffer(GR_GL_DRAW_FRAMEBUFFER, rt->textureFBOID()));
@@ skipping 1192 matching lines @@
             this->setVertexArrayID(gpu, 0);
         }
         int attrCount = gpu->glCaps().maxVertexAttributes();
         if (fDefaultVertexArrayAttribState.count() != attrCount) {
             fDefaultVertexArrayAttribState.resize(attrCount);
         }
         attribState = &fDefaultVertexArrayAttribState;
     }
     return attribState;
 }