Add detection of mip support

R=robertphillips@google.com, jvanverth@google.com

Author: bsalomon@google.com

Review URL: https://codereview.chromium.org/102853005

git-svn-id: http://skia.googlecode.com/svn/trunk@12771 2bbb7eff-a529-9590-31e7-b0007b416f81

4 files changed, 23 insertions, 10 deletions

diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 0b4d96af84..38a5a60c6c 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -962,6 +962,7 @@ void GrDrawTarget::initCopySurfaceDstDesc(const GrSurface* src, GrTextureDesc* d
 
 void GrDrawTargetCaps::reset() {
     f8BitPaletteSupport = false;
+    fMipMapSupport = false;
     fNPOTTextureTileSupport = false;
     fTwoSidedStencilSupport = false;
     fStencilWrapOpsSupport = false;
@@ -983,6 +984,7 @@ void GrDrawTargetCaps::reset() {
 
 GrDrawTargetCaps& GrDrawTargetCaps::operator=(const GrDrawTargetCaps& other) {
     f8BitPaletteSupport = other.f8BitPaletteSupport;
+    fMipMapSupport = other.fMipMapSupport;
     fNPOTTextureTileSupport = other.fNPOTTextureTileSupport;
     fTwoSidedStencilSupport = other.fTwoSidedStencilSupport;
     fStencilWrapOpsSupport = other.fStencilWrapOpsSupport;
@@ -1008,6 +1010,7 @@ SkString GrDrawTargetCaps::dump() const {
     SkString r;
     static const char* gNY[] = {"NO", "YES"};
     r.appendf("8 Bit Palette Support       : %s\n", gNY[f8BitPaletteSupport]);
+    r.appendf("MIP Map Support             : %s\n", gNY[fMipMapSupport]);
     r.appendf("NPOT Texture Tile Support   : %s\n", gNY[fNPOTTextureTileSupport]);
     r.appendf("Two Sided Stencil Support   : %s\n", gNY[fTwoSidedStencilSupport]);
     r.appendf("Stencil Wrap Ops  Support   : %s\n", gNY[fStencilWrapOpsSupport]);
diff --git a/src/gpu/GrDrawTargetCaps.h b/src/gpu/GrDrawTargetCaps.h
index e597e099c9..b316e491c1 100644
--- a/src/gpu/GrDrawTargetCaps.h
+++ b/src/gpu/GrDrawTargetCaps.h
@@ -28,6 +28,9 @@ public:
 
     bool eightBitPaletteSupport() const { return f8BitPaletteSupport; }
     bool npotTextureTileSupport() const { return fNPOTTextureTileSupport; }
+    /** To avoid as-yet-unnecessary complexity we don't allow any partial support of MIP Maps (e.g.
+        only for POT textures) */
+    bool mipMapSupport() const { return fMipMapSupport; }
     bool twoSidedStencilSupport() const { return fTwoSidedStencilSupport; }
     bool stencilWrapOpsSupport() const { return  fStencilWrapOpsSupport; }
     bool hwAALineSupport() const { return fHWAALineSupport; }
@@ -57,6 +60,7 @@ public:
 protected:
     bool f8BitPaletteSupport        : 1;
     bool fNPOTTextureTileSupport    : 1;
+    bool fMipMapSupport             : 1;
     bool fTwoSidedStencilSupport    : 1;
     bool fStencilWrapOpsSupport     : 1;
     bool fHWAALineSupport           : 1;
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 8d8c02254a..8833a05aef 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -285,17 +285,20 @@ void GrGLCaps::init(const GrGLContextInfo& ctxInfo, const GrGLInterface* gli) {
     }
 
     if (kDesktop_GrGLBinding == binding) {
-        if (ctxInfo.version() >= GR_GL_VER(2,0) ||
-            ctxInfo.hasExtension("GL_ARB_texture_non_power_of_two")) {
-            fNPOTTextureTileSupport = true;
-        } else {
-            fNPOTTextureTileSupport = false;
-        }
+        SkASSERT(ctxInfo.version() >= GR_GL_VER(2,0) ||
+                 ctxInfo.hasExtension("GL_ARB_texture_non_power_of_two"));
+        fNPOTTextureTileSupport = true;
+        fMipMapSupport = true;
     } else {
         // Unextended ES2 supports NPOT textures with clamp_to_edge and non-mip filters only
         // ES3 has no limitations.
         fNPOTTextureTileSupport = ctxInfo.version() >= GR_GL_VER(3,0) ||
                                   ctxInfo.hasExtension("GL_OES_texture_npot");
+        // ES2 supports MIP mapping for POT textures but our caps don't allow for limited MIP
+        // support. The OES extension or ES 3.0 allow for MIPS on NPOT textures. So, apparently,
+        // does the undocumented GL_IMG_texture_npot extension. This extension does not seem to
+        // to alllow arbitrary wrap modes, however.
+        fMipMapSupport = fNPOTTextureTileSupport || ctxInfo.hasExtension("GL_IMG_texture_npot");
     }
 
     fHWAALineSupport = (kDesktop_GrGLBinding == binding);
diff --git a/src/gpu/gl/GrGpuGL.cpp b/src/gpu/gl/GrGpuGL.cpp
index 4b5221c31b..7ab4bc1fcb 100644
--- a/src/gpu/gl/GrGpuGL.cpp
+++ b/src/gpu/gl/GrGpuGL.cpp
@@ -2028,11 +2028,14 @@ void GrGpuGL::bindTexture(int unitIdx, const GrTextureParams& params, GrGLTextur
         GR_GL_LINEAR,
         GR_GL_LINEAR
     };
-    newTexParams.fMinFilter = glMinFilterModes[params.filterMode()];
-    newTexParams.fMagFilter = glMagFilterModes[params.filterMode()];
+    GrTextureParams::FilterMode filterMode = params.filterMode();
+    if (!this->caps()->mipMapSupport() && GrTextureParams::kMipMap_FilterMode == filterMode) {
+        filterMode = GrTextureParams::kBilerp_FilterMode;
+    }
+    newTexParams.fMinFilter = glMinFilterModes[filterMode];
+    newTexParams.fMagFilter = glMagFilterModes[filterMode];
 
-    if (params.filterMode() == GrTextureParams::kMipMap_FilterMode &&
-        texture->mipMapsAreDirty()) {
+    if (GrTextureParams::kMipMap_FilterMode == filterMode && texture->mipMapsAreDirty()) {
 //        GL_CALL(Hint(GR_GL_GENERATE_MIPMAP_HINT,GR_GL_NICEST));
         GL_CALL(GenerateMipmap(GR_GL_TEXTURE_2D));
         texture->dirtyMipMaps(false);