[core] move gl::Context to Backend and refactor View

4 files changed, 46 insertions, 44 deletions

diff --git a/src/mbgl/renderer/painter.cpp b/src/mbgl/renderer/painter.cpp
index ee7ef6d212..fc61d6e0a0 100644
--- a/src/mbgl/renderer/painter.cpp
+++ b/src/mbgl/renderer/painter.cpp
@@ -31,6 +31,8 @@
 #include <mbgl/util/mat3.hpp>
 #include <mbgl/util/string.hpp>
 
+#include <mbgl/util/offscreen_texture.hpp>
+
 #include <cassert>
 #include <algorithm>
 #include <iostream>
@@ -40,8 +42,9 @@ namespace mbgl {
 
 using namespace style;
 
-Painter::Painter(const TransformState& state_)
-    : state(state_),
+Painter::Painter(gl::Context& context_, const TransformState& state_)
+    : context(context_),
+      state(state_),
       tileTriangleVertexBuffer(context.createVertexBuffer(std::vector<FillVertex> {{
             { 0,            0 },
             { util::EXTENT, 0 },
@@ -71,9 +74,6 @@ Painter::Painter(const TransformState& state_)
 #ifndef NDEBUG
     overdrawShaders = std::make_unique<Shaders>(context, gl::Shader::Overdraw);
 #endif
-
-    // Reset GL values
-    context.setDirtyState();
 }
 
 Painter::~Painter() = default;
@@ -93,9 +93,10 @@ void Painter::cleanup() {
 }
 
 void Painter::render(const Style& style, const FrameData& frame_, View& view, SpriteAtlas& annotationSpriteAtlas) {
-    context.viewport.setDefaultValue(
-        { 0, 0, view.getFramebufferSize()[0], view.getFramebufferSize()[1] });
     frame = frame_;
+    if (frame.contextMode == GLContextMode::Shared) {
+        context.setDirtyState();
+    }
 
     PaintParameters parameters {
 #ifndef NDEBUG
@@ -126,12 +127,14 @@ void Painter::render(const Style& style, const FrameData& frame_, View& view, Sp
     frameHistory.record(frame.timePoint, state.getZoom(),
         frame.mapMode == MapMode::Continuous ? util::DEFAULT_FADE_DURATION : Milliseconds(0));
 
+
     // - UPLOAD PASS -------------------------------------------------------------------------------
     // Uploads all required buffers and images before we do any actual rendering.
     {
         MBGL_DEBUG_GROUP("upload");
 
         spriteAtlas->upload(context, 0);
+
         lineAtlas->upload(context, 0);
         glyphAtlas->upload(context, 0);
         frameHistory.upload(context, 0);
@@ -149,10 +152,8 @@ void Painter::render(const Style& style, const FrameData& frame_, View& view, Sp
     // tiles whatsoever.
     {
         MBGL_DEBUG_GROUP("clear");
-        context.bindFramebuffer.setDirty();
         view.bind();
-        context.viewport.reset();
-        context.stencilFunc.reset();
+        context.stencilFunc = { gl::StencilTestFunction::Always, 0, ~0u };
         context.stencilTest = true;
         context.stencilMask = 0xFF;
         context.depthTest = false;
@@ -249,10 +250,6 @@ void Painter::render(const Style& style, const FrameData& frame_, View& view, Sp
 
         context.vertexArrayObject = 0;
     }
-
-    if (frame.contextMode == GLContextMode::Shared) {
-        context.setDirtyState();
-    }
 }
 
 template <class Iterator>
@@ -296,17 +293,21 @@ void Painter::renderPass(PaintParameters& parameters,
             renderBackground(parameters, *layer.as<BackgroundLayer>());
         } else if (layer.is<CustomLayer>()) {
             MBGL_DEBUG_GROUP(layer.baseImpl->id + " - custom");
+
+            // Reset GL state to a known state so the CustomLayer always has a clean slate.
             context.vertexArrayObject = 0;
             context.depthFunc = gl::DepthTestFunction::LessEqual;
             context.depthTest = true;
             context.depthMask = false;
             context.stencilTest = false;
             setDepthSublayer(0);
+
             layer.as<CustomLayer>()->impl->render(state);
-            context.setDirtyState();
-            context.bindFramebuffer.setDirty();
+
+            // Reset the view back to our original one, just in case the CustomLayer changed
+            // the viewport or Framebuffer.
             parameters.view.bind();
-            context.viewport.reset();
+            context.setDirtyState();
         } else {
             MBGL_DEBUG_GROUP(layer.baseImpl->id + " - " + util::toString(item.tile->id));
             if (item.bucket->needsClipping()) {
diff --git a/src/mbgl/renderer/painter.hpp b/src/mbgl/renderer/painter.hpp
index d2c89c04a9..f339ed1aed 100644
--- a/src/mbgl/renderer/painter.hpp
+++ b/src/mbgl/renderer/painter.hpp
@@ -68,7 +68,7 @@ struct FrameData {
 
 class Painter : private util::noncopyable {
 public:
-    Painter(const TransformState&);
+    Painter(gl::Context&, const TransformState&);
     ~Painter();
 
     void render(const style::Style&,
@@ -153,6 +153,9 @@ private:
     }
 #endif
 
+private:
+    gl::Context& context;
+
     mat4 projMatrix;
 
     std::array<float, 2> pixelsToGLUnits;
@@ -169,8 +172,6 @@ private:
 
     int indent = 0;
 
-    gl::Context context;
-
     RenderPass pass = RenderPass::Opaque;
 
     int numSublayers = 3;
diff --git a/src/mbgl/renderer/painter_debug.cpp b/src/mbgl/renderer/painter_debug.cpp
index ca961f84e7..e57bb2205e 100644
--- a/src/mbgl/renderer/painter_debug.cpp
+++ b/src/mbgl/renderer/painter_debug.cpp
@@ -89,7 +89,7 @@ void Painter::renderDebugFrame(const mat4 &matrix) {
 }
 
 #ifndef NDEBUG
-void Painter::renderClipMasks(PaintParameters& parameters) {
+void Painter::renderClipMasks(PaintParameters&) {
     context.stencilTest = false;
     context.depthTest = false;
     context.program = 0;
@@ -100,13 +100,13 @@ void Painter::renderClipMasks(PaintParameters& parameters) {
     context.rasterPos = { -1, -1, 0, 0 };
 
     // Read the stencil buffer
-    const auto& fbSize = parameters.view.getFramebufferSize();
-    auto pixels = std::make_unique<uint8_t[]>(fbSize[0] * fbSize[1]);
+    const auto viewport = context.viewport.getCurrentValue();
+    auto pixels = std::make_unique<uint8_t[]>(viewport.width * viewport.height);
     MBGL_CHECK_ERROR(glReadPixels(
-                0,                // GLint x
-                0,                // GLint y
-                fbSize[0],        // GLsizei width
-                fbSize[1],        // GLsizei height
+                viewport.x,         // GLint x
+                viewport.y,         // GLint y
+                viewport.width,   // GLsizei width
+                viewport.height,  // GLsizei height
                 GL_STENCIL_INDEX, // GLenum format
                 GL_UNSIGNED_BYTE, // GLenum type
                 pixels.get()      // GLvoid * data
@@ -114,22 +114,21 @@ void Painter::renderClipMasks(PaintParameters& parameters) {
 
     // Scale the Stencil buffer to cover the entire color space.
     auto it = pixels.get();
-    auto end = it + fbSize[0] * fbSize[1];
+    auto end = it + viewport.width * viewport.height;
     const auto factor = 255.0f / *std::max_element(it, end);
     for (; it != end; ++it) {
         *it *= factor;
     }
 
-    MBGL_CHECK_ERROR(glWindowPos2i(0, 0));
-    MBGL_CHECK_ERROR(glDrawPixels(fbSize[0], fbSize[1], GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels.get()));
-#else
-    (void)parameters;
+    MBGL_CHECK_ERROR(glWindowPos2i(viewport.x, viewport.y));
+    MBGL_CHECK_ERROR(glDrawPixels(viewport.width, viewport.height, GL_LUMINANCE, GL_UNSIGNED_BYTE,
+                                  pixels.get()));
 #endif // MBGL_USE_GLES2
 }
 #endif // NDEBUG
 
 #ifndef NDEBUG
-void Painter::renderDepthBuffer(PaintParameters& parameters) {
+void Painter::renderDepthBuffer(PaintParameters&) {
     context.stencilTest = false;
     context.depthTest = false;
     context.program = 0;
@@ -140,27 +139,26 @@ void Painter::renderDepthBuffer(PaintParameters& parameters) {
     context.rasterPos = { -1, -1, 0, 0 };
 
     // Read the stencil buffer
-    const auto& fbSize = parameters.view.getFramebufferSize();
-    auto pixels = std::make_unique<GLubyte[]>(fbSize[0] * fbSize[1]);
+    const auto viewport = context.viewport.getCurrentValue();
+    auto pixels = std::make_unique<uint8_t[]>(viewport.width * viewport.height);
 
     const double base = 1.0 / (1.0 - depthRangeSize);
     glPixelTransferf(GL_DEPTH_SCALE, base);
     glPixelTransferf(GL_DEPTH_BIAS, 1.0 - base);
 
     MBGL_CHECK_ERROR(glReadPixels(
-                0,                  // GLint x
-                0,                  // GLint y
-                fbSize[0],          // GLsizei width
-                fbSize[1],          // GLsizei height
+                viewport.x,         // GLint x
+                viewport.y,         // GLint y
+                viewport.width,     // GLsizei width
+                viewport.height,    // GLsizei height
                 GL_DEPTH_COMPONENT, // GLenum format
                 GL_UNSIGNED_BYTE,   // GLenum type
                 pixels.get()        // GLvoid * data
                 ));
 
-    MBGL_CHECK_ERROR(glWindowPos2i(0, 0));
-    MBGL_CHECK_ERROR(glDrawPixels(fbSize[0], fbSize[1], GL_LUMINANCE, GL_UNSIGNED_BYTE, pixels.get()));
-#else
-    (void)parameters;
+    MBGL_CHECK_ERROR(glWindowPos2i(viewport.x, viewport.y));
+    MBGL_CHECK_ERROR(glDrawPixels(viewport.width, viewport.height, GL_LUMINANCE, GL_UNSIGNED_BYTE,
+                                  pixels.get()));
 #endif // MBGL_USE_GLES2
 }
 #endif // NDEBUG
diff --git a/src/mbgl/renderer/painter_fill.cpp b/src/mbgl/renderer/painter_fill.cpp
index 1fc5f11079..b6606ca40b 100644
--- a/src/mbgl/renderer/painter_fill.cpp
+++ b/src/mbgl/renderer/painter_fill.cpp
@@ -30,7 +30,9 @@ void Painter::renderFill(PaintParameters& parameters,
     const bool isOutlineColorDefined = !properties.fillOutlineColor.isUndefined();
     Color strokeColor = isOutlineColorDefined? properties.fillOutlineColor : fillColor;
 
-    auto worldSize = util::convert<GLfloat>(parameters.view.getFramebufferSize());
+    const auto viewport = context.viewport.getCurrentValue();
+    const std::array<GLfloat, 2> worldSize{ { static_cast<GLfloat>(viewport.width),
+                                              static_cast<GLfloat>(viewport.height) } };
 
     bool pattern = !properties.fillPattern.value.from.empty();
     bool outline = properties.fillAntialias && !pattern && isOutlineColorDefined;