From 4edb2bc22281bc29822d46c3f39a9f99e40afa49 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Konstantin=20K=C3=A4fer?= <mail@kkaefer.com>
Date: Fri, 5 Feb 2016 16:10:19 +0100
Subject: [PATCH] [core] draw clipping masks from ClipIDGenerator rather than
 Sources

---
 src/mbgl/map/source.cpp                |  8 ------
 src/mbgl/map/source.hpp                |  1 -
 src/mbgl/renderer/painter.cpp          |  2 +-
 src/mbgl/renderer/painter.hpp          |  3 +--
 src/mbgl/renderer/painter_clipping.cpp | 35 ++++++++++++++------------
 5 files changed, 21 insertions(+), 28 deletions(-)

diff --git a/src/mbgl/map/source.cpp b/src/mbgl/map/source.cpp
index 7f9b47440..55d87d988 100644
--- a/src/mbgl/map/source.cpp
+++ b/src/mbgl/map/source.cpp
@@ -173,14 +173,6 @@ void Source::updateMatrices(const mat4 &projMatrix, const TransformState &transf
     }
 }
 
-void Source::drawClippingMasks(Painter &painter) {
-    for (const auto& pair : tiles) {
-        Tile &tile = *pair.second;
-        MBGL_DEBUG_GROUP(std::string { "mask: " } + std::string(tile.id));
-        painter.drawClippingMask(tile.matrix, tile.clip);
-    }
-}
-
 void Source::finishRender(Painter &painter) {
     for (const auto& pair : tiles) {
         Tile &tile = *pair.second;
diff --git a/src/mbgl/map/source.hpp b/src/mbgl/map/source.hpp
index d9146c1fd..cca160a72 100644
--- a/src/mbgl/map/source.hpp
+++ b/src/mbgl/map/source.hpp
@@ -60,7 +60,6 @@ public:
     bool update(const StyleUpdateParameters&);
 
     void updateMatrices(const mat4 &projMatrix, const TransformState &transform);
-    void drawClippingMasks(Painter &painter);
     void finishRender(Painter &painter);
 
     std::forward_list<Tile *> getLoadedTiles() const;
diff --git a/src/mbgl/renderer/painter.cpp b/src/mbgl/renderer/painter.cpp
index 0fd76314d..fe0118952 100644
--- a/src/mbgl/renderer/painter.cpp
+++ b/src/mbgl/renderer/painter.cpp
@@ -151,7 +151,7 @@ void Painter::render(const Style& style, const FrameData& frame_, SpriteAtlas& a
             source->updateMatrices(projMatrix, state);
         }
 
-        drawClippingMasks(sources);
+        drawClippingMasks(generator.getStencils());
     }
 
     frameHistory.record(data.getAnimationTime(), state.getZoom());
diff --git a/src/mbgl/renderer/painter.hpp b/src/mbgl/renderer/painter.hpp
index e2949681c..8ab0a4980 100644
--- a/src/mbgl/renderer/painter.hpp
+++ b/src/mbgl/renderer/painter.hpp
@@ -93,8 +93,7 @@ public:
     float contrastFactor(float contrast);
     std::array<float, 3> spinWeights(float spin_value);
 
-    void drawClippingMasks(const std::set<Source*>&);
-    void drawClippingMask(const mat4& matrix, const ClipID& clip);
+    void drawClippingMasks(const std::map<TileID, ClipID>&);
 
     bool needsAnimation() const;
 
diff --git a/src/mbgl/renderer/painter_clipping.cpp b/src/mbgl/renderer/painter_clipping.cpp
index 699465041..618c1093a 100644
--- a/src/mbgl/renderer/painter_clipping.cpp
+++ b/src/mbgl/renderer/painter_clipping.cpp
@@ -6,31 +6,34 @@
 
 using namespace mbgl;
 
-void Painter::drawClippingMasks(const std::set<Source*>& sources) {
+
+void Painter::drawClippingMasks(const std::map<TileID, ClipID>& stencils) {
     MBGL_DEBUG_GROUP("clipping masks");
 
+    mat4 matrix;
+    const GLuint mask = 0b11111111;
+
     config.program = plainShader->program;
     config.stencilOp.reset();
     config.stencilTest = GL_TRUE;
-    config.depthFunc.reset();
-    config.depthTest = GL_TRUE;
+    config.depthTest = GL_FALSE;
     config.depthMask = GL_FALSE;
     config.colorMask = { GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE };
-    config.depthRange = { 1.0f, 1.0f };
+    config.stencilMask = mask;
 
     coveringPlainArray.bind(*plainShader, tileStencilBuffer, BUFFER_OFFSET_0);
 
-    for (const auto& source : sources) {
-        source->drawClippingMasks(*this);
+    for (const auto& stencil : stencils) {
+        const auto& id = stencil.first;
+        const auto& clip = stencil.second;
+
+        MBGL_DEBUG_GROUP(std::string{ "mask: " } + std::string(id));
+        state.matrixFor(matrix, id, id.z);
+        matrix::multiply(matrix, projMatrix, matrix);
+        plainShader->u_matrix = matrix;
+
+        const GLint ref = (GLint)(clip.reference.to_ulong());
+        config.stencilFunc = { GL_ALWAYS, ref, mask };
+        MBGL_CHECK_ERROR(glDrawArrays(GL_TRIANGLES, 0, (GLsizei)tileStencilBuffer.index()));
     }
 }
-
-void Painter::drawClippingMask(const mat4& matrix, const ClipID &clip) {
-    plainShader->u_matrix = matrix;
-
-    const GLint ref = (GLint)(clip.reference.to_ulong());
-    const GLuint mask = (GLuint)(clip.mask.to_ulong());
-    config.stencilFunc = { GL_ALWAYS, ref, mask };
-    config.stencilMask = mask;
-    MBGL_CHECK_ERROR(glDrawArrays(GL_TRIANGLES, 0, (GLsizei)tileStencilBuffer.index()));
-}