citra_qt, video_core: Screenshot functionality

Allows capturing screenshot at the current internal resolution (native for software renderer), but a setting is available to capture it in other resolutions. The screenshot is saved to a single PNG in the current layout.

src/video_core/renderer_opengl/gl_rasterizer_cache.cpp

@@ -24,7 +24,6 @@
 #include "common/vector_math.h"
 #include "core/frontend/emu_window.h"
 #include "core/memory.h"
-#include "core/settings.h"
 #include "video_core/pica_state.h"
 #include "video_core/renderer_base.h"
 #include "video_core/renderer_opengl/gl_rasterizer_cache.h"
@@ -78,12 +77,6 @@ constexpr auto RangeFromInterval(Map& map, const Interval& interval) {
     return boost::make_iterator_range(map.equal_range(interval));
 }
 
-static u16 GetResolutionScaleFactor() {
-    return !Settings::values.resolution_factor
-               ? VideoCore::g_renderer->GetRenderWindow().GetFramebufferLayout().GetScalingRatio()
-               : Settings::values.resolution_factor;
-}
-
 template <bool morton_to_gl, PixelFormat format>
 static void MortonCopyTile(u32 stride, u8* tile_buffer, u8* gl_buffer) {
     constexpr u32 bytes_per_pixel = SurfaceParams::GetFormatBpp(format) / 8;
@@ -1360,9 +1353,9 @@ SurfaceSurfaceRect_Tuple RasterizerCacheOpenGL::GetFramebufferSurfaces(
     const auto& config = regs.framebuffer.framebuffer;
 
     // update resolution_scale_factor and reset cache if changed
-    static u16 resolution_scale_factor = GetResolutionScaleFactor();
-    if (resolution_scale_factor != GetResolutionScaleFactor()) {
-        resolution_scale_factor = GetResolutionScaleFactor();
+    static u16 resolution_scale_factor = VideoCore::GetResolutionScaleFactor();
+    if (resolution_scale_factor != VideoCore::GetResolutionScaleFactor()) {
+        resolution_scale_factor = VideoCore::GetResolutionScaleFactor();
         FlushAll();
         while (!surface_cache.empty())
             UnregisterSurface(*surface_cache.begin()->second.begin());

src/video_core/renderer_opengl/renderer_opengl.cpp

@@ -140,7 +140,39 @@ void RendererOpenGL::SwapBuffers() {
         }
     }
 
-    DrawScreens();
+    if (VideoCore::g_renderer_screenshot_requested) {
+        // Draw this frame to the screenshot framebuffer
+        screenshot_framebuffer.Create();
+        GLuint old_read_fb = state.draw.read_framebuffer;
+        GLuint old_draw_fb = state.draw.draw_framebuffer;
+        state.draw.read_framebuffer = state.draw.draw_framebuffer = screenshot_framebuffer.handle;
+        state.Apply();
+
+        Layout::FramebufferLayout layout{VideoCore::g_screenshot_framebuffer_layout};
+
+        GLuint renderbuffer;
+        glGenRenderbuffers(1, &renderbuffer);
+        glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
+        glRenderbufferStorage(GL_RENDERBUFFER, GL_RGB8, layout.width, layout.height);
+        glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER,
+                                  renderbuffer);
+
+        DrawScreens(layout);
+
+        glReadPixels(0, 0, layout.width, layout.height, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV,
+                     VideoCore::g_screenshot_bits);
+
+        screenshot_framebuffer.Release();
+        state.draw.read_framebuffer = old_read_fb;
+        state.draw.draw_framebuffer = old_draw_fb;
+        state.Apply();
+        glDeleteRenderbuffers(1, &renderbuffer);
+
+        VideoCore::g_screenshot_complete_callback();
+        VideoCore::g_renderer_screenshot_requested = false;
+    }
+
+    DrawScreens(render_window.GetFramebufferLayout());
 
     Core::System::GetInstance().perf_stats.EndSystemFrame();
 
@@ -386,14 +418,13 @@ void RendererOpenGL::DrawSingleScreenRotated(const ScreenInfo& screen_info, floa
 /**
  * Draws the emulated screens to the emulator window.
  */
-void RendererOpenGL::DrawScreens() {
+void RendererOpenGL::DrawScreens(const Layout::FramebufferLayout& layout) {
     if (VideoCore::g_renderer_bg_color_update_requested.exchange(false)) {
         // Update background color before drawing
         glClearColor(Settings::values.bg_red, Settings::values.bg_green, Settings::values.bg_blue,
                      0.0f);
     }
 
-    auto layout = render_window.GetFramebufferLayout();
     const auto& top_screen = layout.top_screen;
     const auto& bottom_screen = layout.bottom_screen;
 

src/video_core/renderer_opengl/renderer_opengl.h

@@ -13,6 +13,10 @@
 #include "video_core/renderer_opengl/gl_resource_manager.h"
 #include "video_core/renderer_opengl/gl_state.h"
 
+namespace Layout {
+class FramebufferLayout;
+}
+
 namespace OpenGL {
 
 /// Structure used for storing information about the textures for each 3DS screen
@@ -50,7 +54,7 @@ private:
     void InitOpenGLObjects();
     void ConfigureFramebufferTexture(TextureInfo& texture,
                                      const GPU::Regs::FramebufferConfig& framebuffer);
-    void DrawScreens();
+    void DrawScreens(const Layout::FramebufferLayout& layout);
     void DrawSingleScreenRotated(const ScreenInfo& screen_info, float x, float y, float w, float h);
     void UpdateFramerate();
 
@@ -66,6 +70,7 @@ private:
     OGLVertexArray vertex_array;
     OGLBuffer vertex_buffer;
     OGLProgram shader;
+    OGLFramebuffer screenshot_framebuffer;
 
     /// Display information for top and bottom screens respectively
     std::array<ScreenInfo, 3> screen_infos;