Split out GrBitmapTextContext from GrTextContext.

This is a stepping stone to having a variety of different text context types
(bitmaps, distance fields, NV path rendering).

R=bsalomon@google.com

Review URL: https://codereview.chromium.org/27199002

git-svn-id: http://skia.googlecode.com/svn/trunk@11820 2bbb7eff-a529-9590-31e7-b0007b416f81

1 files changed, 248 insertions, 0 deletions

diff --git a/src/gpu/GrBitmapTextContext.cpp b/src/gpu/GrBitmapTextContext.cpp
new file mode 100755
index 0000000000..7a99f093e5
--- /dev/null
+++ b/src/gpu/GrBitmapTextContext.cpp
@@ -0,0 +1,248 @@
+/*
+ * Copyright 2013 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrBitmapTextContext.h"
+#include "GrAtlas.h"
+#include "GrDrawTarget.h"
+#include "GrFontScaler.h"
+#include "GrIndexBuffer.h"
+#include "GrTextStrike.h"
+#include "GrTextStrike_impl.h"
+#include "SkPath.h"
+#include "SkRTConf.h"
+#include "SkStrokeRec.h"
+#include "effects/GrCustomCoordsTextureEffect.h"
+
+static const int kGlyphCoordsAttributeIndex = 1;
+
+SK_CONF_DECLARE(bool, c_DumpFontCache, "gpu.dumpFontCache", false,
+                "Dump the contents of the font cache before every purge.");
+
+GrBitmapTextContext::GrBitmapTextContext(GrContext* context, const GrPaint& paint) :
+                                         GrTextContext(context, paint) {
+    fAutoMatrix.setIdentity(fContext, &fPaint);
+
+    fStrike = NULL;
+
+    fCurrTexture = NULL;
+    fCurrVertex = 0;
+
+    fVertices = NULL;
+    fMaxVertices = 0;
+}
+
+GrBitmapTextContext::~GrBitmapTextContext() {
+    this->flushGlyphs();
+}
+
+void GrBitmapTextContext::flushGlyphs() {
+    if (NULL == fDrawTarget) {
+        return;
+    }
+
+    GrDrawState* drawState = fDrawTarget->drawState();
+    GrDrawState::AutoRestoreEffects are(drawState);
+    drawState->setFromPaint(fPaint, SkMatrix::I(), fContext->getRenderTarget());
+
+    if (fCurrVertex > 0) {
+        // setup our sampler state for our text texture/atlas
+        SkASSERT(GrIsALIGN4(fCurrVertex));
+        SkASSERT(fCurrTexture);
+        GrTextureParams params(SkShader::kRepeat_TileMode, GrTextureParams::kNone_FilterMode);
+
+        // This effect could be stored with one of the cache objects (atlas?)
+        drawState->addCoverageEffect(
+                                GrCustomCoordsTextureEffect::Create(fCurrTexture, params),
+                                kGlyphCoordsAttributeIndex)->unref();
+
+        if (!GrPixelConfigIsAlphaOnly(fCurrTexture->config())) {
+            if (kOne_GrBlendCoeff != fPaint.getSrcBlendCoeff() ||
+                kISA_GrBlendCoeff != fPaint.getDstBlendCoeff() ||
+                fPaint.numColorStages()) {
+                GrPrintf("LCD Text will not draw correctly.\n");
+            }
+            // setup blend so that we get mask * paintColor + (1-mask)*dstColor
+            drawState->setBlendConstant(fPaint.getColor());
+            drawState->setBlendFunc(kConstC_GrBlendCoeff, kISC_GrBlendCoeff);
+            // don't modulate by the paint's color in the frag since we're
+            // already doing it via the blend const.
+            drawState->setColor(0xffffffff);
+        } else {
+            // set back to normal in case we took LCD path previously.
+            drawState->setBlendFunc(fPaint.getSrcBlendCoeff(), fPaint.getDstBlendCoeff());
+            drawState->setColor(fPaint.getColor());
+        }
+
+        int nGlyphs = fCurrVertex / 4;
+        fDrawTarget->setIndexSourceToBuffer(fContext->getQuadIndexBuffer());
+        fDrawTarget->drawIndexedInstances(kTriangles_GrPrimitiveType,
+                                          nGlyphs,
+                                          4, 6);
+        fDrawTarget->resetVertexSource();
+        fVertices = NULL;
+        fMaxVertices = 0;
+        fCurrVertex = 0;
+        SkSafeSetNull(fCurrTexture);
+    }
+}
+
+namespace {
+
+// position + texture coord
+extern const GrVertexAttrib gTextVertexAttribs[] = {
+    {kVec2f_GrVertexAttribType, 0,               kPosition_GrVertexAttribBinding},
+    {kVec2f_GrVertexAttribType, sizeof(GrPoint), kEffect_GrVertexAttribBinding}
+};
+
+};
+
+void GrBitmapTextContext::drawPackedGlyph(GrGlyph::PackedID packed,
+                                          GrFixed vx, GrFixed vy,
+                                          GrFontScaler* scaler) {
+    if (NULL == fDrawTarget) {
+        return;
+    }
+    if (NULL == fStrike) {
+        fStrike = fContext->getFontCache()->getStrike(scaler);
+    }
+
+    GrGlyph* glyph = fStrike->getGlyph(packed, scaler);
+    if (NULL == glyph || glyph->fBounds.isEmpty()) {
+        return;
+    }
+
+    vx += SkIntToFixed(glyph->fBounds.fLeft);
+    vy += SkIntToFixed(glyph->fBounds.fTop);
+
+    // keep them as ints until we've done the clip-test
+    GrFixed width = glyph->fBounds.width();
+    GrFixed height = glyph->fBounds.height();
+
+    // check if we clipped out
+    if (true || NULL == glyph->fPlot) {
+        int x = vx >> 16;
+        int y = vy >> 16;
+        if (fClipRect.quickReject(x, y, x + width, y + height)) {
+//            SkCLZ(3);    // so we can set a break-point in the debugger
+            return;
+        }
+    }
+
+    if (NULL == glyph->fPlot) {
+        if (fStrike->getGlyphAtlas(glyph, scaler)) {
+            goto HAS_ATLAS;
+        }
+
+        // try to clear out an unused plot before we flush
+        fContext->getFontCache()->freePlotExceptFor(fStrike);
+        if (fStrike->getGlyphAtlas(glyph, scaler)) {
+            goto HAS_ATLAS;
+        }
+
+        if (c_DumpFontCache) {
+#ifdef SK_DEVELOPER
+            fContext->getFontCache()->dump();
+#endif
+        }
+
+        // before we purge the cache, we must flush any accumulated draws
+        this->flushGlyphs();
+        fContext->flush();
+
+        // try to purge
+        fContext->getFontCache()->purgeExceptFor(fStrike);
+        // need to use new flush count here
+        if (fStrike->getGlyphAtlas(glyph, scaler)) {
+            goto HAS_ATLAS;
+        }
+
+        if (NULL == glyph->fPath) {
+            SkPath* path = SkNEW(SkPath);
+            if (!scaler->getGlyphPath(glyph->glyphID(), path)) {
+                // flag the glyph as being dead?
+                delete path;
+                return;
+            }
+            glyph->fPath = path;
+        }
+
+        GrContext::AutoMatrix am;
+        SkMatrix translate;
+        translate.setTranslate(SkFixedToScalar(vx - SkIntToFixed(glyph->fBounds.fLeft)),
+                               SkFixedToScalar(vy - SkIntToFixed(glyph->fBounds.fTop)));
+        GrPaint tmpPaint(fPaint);
+        am.setPreConcat(fContext, translate, &tmpPaint);
+        SkStrokeRec stroke(SkStrokeRec::kFill_InitStyle);
+        fContext->drawPath(tmpPaint, *glyph->fPath, stroke);
+        return;
+    }
+
+HAS_ATLAS:
+    SkASSERT(glyph->fPlot);
+    GrDrawTarget::DrawToken drawToken = fDrawTarget->getCurrentDrawToken();
+    glyph->fPlot->setDrawToken(drawToken);
+
+    // now promote them to fixed (TODO: Rethink using fixed pt).
+    width = SkIntToFixed(width);
+    height = SkIntToFixed(height);
+
+    GrTexture* texture = glyph->fPlot->texture();
+    SkASSERT(texture);
+
+    if (fCurrTexture != texture || fCurrVertex + 4 > fMaxVertices) {
+        this->flushGlyphs();
+        fCurrTexture = texture;
+        fCurrTexture->ref();
+    }
+
+    if (NULL == fVertices) {
+       // If we need to reserve vertices allow the draw target to suggest
+        // a number of verts to reserve and whether to perform a flush.
+        fMaxVertices = kMinRequestedVerts;
+        fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
+            SK_ARRAY_COUNT(gTextVertexAttribs));
+        bool flush = fDrawTarget->geometryHints(&fMaxVertices, NULL);
+        if (flush) {
+            this->flushGlyphs();
+            fContext->flush();
+            fDrawTarget->drawState()->setVertexAttribs<gTextVertexAttribs>(
+                SK_ARRAY_COUNT(gTextVertexAttribs));
+        }
+        fMaxVertices = kDefaultRequestedVerts;
+        // ignore return, no point in flushing again.
+        fDrawTarget->geometryHints(&fMaxVertices, NULL);
+
+        int maxQuadVertices = 4 * fContext->getQuadIndexBuffer()->maxQuads();
+        if (fMaxVertices < kMinRequestedVerts) {
+            fMaxVertices = kDefaultRequestedVerts;
+        } else if (fMaxVertices > maxQuadVertices) {
+            // don't exceed the limit of the index buffer
+            fMaxVertices = maxQuadVertices;
+        }
+        bool success = fDrawTarget->reserveVertexAndIndexSpace(fMaxVertices,
+                                                               0,
+                                                               GrTCast<void**>(&fVertices),
+                                                               NULL);
+        GrAlwaysAssert(success);
+        SkASSERT(2*sizeof(GrPoint) == fDrawTarget->getDrawState().getVertexSize());
+    }
+
+    GrFixed tx = SkIntToFixed(glyph->fAtlasLocation.fX);
+    GrFixed ty = SkIntToFixed(glyph->fAtlasLocation.fY);
+
+    fVertices[2*fCurrVertex].setRectFan(SkFixedToFloat(vx),
+                                        SkFixedToFloat(vy),
+                                        SkFixedToFloat(vx + width),
+                                        SkFixedToFloat(vy + height),
+                                        2 * sizeof(SkPoint));
+    fVertices[2*fCurrVertex+1].setRectFan(SkFixedToFloat(texture->normalizeFixedX(tx)),
+                                          SkFixedToFloat(texture->normalizeFixedY(ty)),
+                                          SkFixedToFloat(texture->normalizeFixedX(tx + width)),
+                                          SkFixedToFloat(texture->normalizeFixedY(ty + height)),
+                                          2 * sizeof(SkPoint));
+    fCurrVertex += 4;
+}