1 files changed, 128 insertions, 0 deletions
diff --git a/src/video_core/renderer_opengl/present/window_adapt_pass.cpp b/src/video_core/renderer_opengl/present/window_adapt_pass.cpp
new file mode 100644
index 000000000..168fa1aea
--- /dev/null
+++ b/src/video_core/renderer_opengl/present/window_adapt_pass.cpp
@@ -0,0 +1,128 @@
+// SPDX-FileCopyrightText: Copyright 2024 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "common/settings.h"
+#include "video_core/host_shaders/opengl_present_vert.h"
+#include "video_core/renderer_opengl/gl_device.h"
+#include "video_core/renderer_opengl/gl_shader_manager.h"
+#include "video_core/renderer_opengl/gl_shader_util.h"
+#include "video_core/renderer_opengl/present/window_adapt_pass.h"
+
+namespace OpenGL {
+
+namespace {
+constexpr GLint PositionLocation = 0;
+constexpr GLint TexCoordLocation = 1;
+constexpr GLint ModelViewMatrixLocation = 0;
+
+struct ScreenRectVertex {
+    constexpr ScreenRectVertex(u32 x, u32 y, GLfloat u, GLfloat v)
+        : position{{static_cast<GLfloat>(x), static_cast<GLfloat>(y)}}, tex_coord{{u, v}} {}
+
+    std::array<GLfloat, 2> position;
+    std::array<GLfloat, 2> tex_coord;
+};
+
+/**
+ * Defines a 1:1 pixel orthographic projection matrix with (0,0) on the top-left
+ * corner and (width, height) on the lower-bottom.
+ *
+ * The projection part of the matrix is trivial, hence these operations are represented
+ * by a 3x2 matrix.
+ */
+std::array<GLfloat, 3 * 2> MakeOrthographicMatrix(float width, float height) {
+    std::array<GLfloat, 3 * 2> matrix; // Laid out in column-major order
+
+    // clang-format off
+    matrix[0] = 2.f / width; matrix[2] =  0.f;          matrix[4] = -1.f;
+    matrix[1] = 0.f;         matrix[3] = -2.f / height; matrix[5] =  1.f;
+    // Last matrix row is implicitly assumed to be [0, 0, 1].
+    // clang-format on
+
+    return matrix;
+}
+} // namespace
+
+WindowAdaptPass::WindowAdaptPass(const Device& device_, OGLSampler&& sampler_,
+                                 std::string_view frag_source)
+    : device(device_), sampler(std::move(sampler_)) {
+    vert = CreateProgram(HostShaders::OPENGL_PRESENT_VERT, GL_VERTEX_SHADER);
+    frag = CreateProgram(frag_source, GL_FRAGMENT_SHADER);
+
+    // Generate VBO handle for drawing
+    vertex_buffer.Create();
+
+    // Attach vertex data to VAO
+    glNamedBufferData(vertex_buffer.handle, sizeof(ScreenRectVertex) * 4, nullptr, GL_STREAM_DRAW);
+
+    // Query vertex buffer address when the driver supports unified vertex attributes
+    if (device.HasVertexBufferUnifiedMemory()) {
+        glMakeNamedBufferResidentNV(vertex_buffer.handle, GL_READ_ONLY);
+        glGetNamedBufferParameterui64vNV(vertex_buffer.handle, GL_BUFFER_GPU_ADDRESS_NV,
+                                         &vertex_buffer_address);
+    }
+}
+
+WindowAdaptPass::~WindowAdaptPass() = default;
+
+void WindowAdaptPass::DrawToFramebuffer(ProgramManager& program_manager, GLuint texture,
+                                        const Layout::FramebufferLayout& layout,
+                                        const Common::Rectangle<f32>& crop) {
+    glBindTextureUnit(0, texture);
+
+    const std::array ortho_matrix =
+        MakeOrthographicMatrix(static_cast<float>(layout.width), static_cast<float>(layout.height));
+
+    program_manager.BindPresentPrograms(vert.handle, frag.handle);
+    glProgramUniformMatrix3x2fv(vert.handle, ModelViewMatrixLocation, 1, GL_FALSE,
+                                ortho_matrix.data());
+
+    // Map the coordinates to the screen.
+    const auto& screen = layout.screen;
+    const auto x = screen.left;
+    const auto y = screen.top;
+    const auto w = screen.GetWidth();
+    const auto h = screen.GetHeight();
+
+    const std::array vertices = {
+        ScreenRectVertex(x, y, crop.left, crop.top),
+        ScreenRectVertex(x + w, y, crop.right, crop.top),
+        ScreenRectVertex(x, y + h, crop.left, crop.bottom),
+        ScreenRectVertex(x + w, y + h, crop.right, crop.bottom),
+    };
+    glNamedBufferSubData(vertex_buffer.handle, 0, sizeof(vertices), std::data(vertices));
+
+    glDisable(GL_FRAMEBUFFER_SRGB);
+    glViewportIndexedf(0, 0.0f, 0.0f, static_cast<GLfloat>(layout.width),
+                       static_cast<GLfloat>(layout.height));
+
+    glEnableVertexAttribArray(PositionLocation);
+    glEnableVertexAttribArray(TexCoordLocation);
+    glVertexAttribDivisor(PositionLocation, 0);
+    glVertexAttribDivisor(TexCoordLocation, 0);
+    glVertexAttribFormat(PositionLocation, 2, GL_FLOAT, GL_FALSE,
+                         offsetof(ScreenRectVertex, position));
+    glVertexAttribFormat(TexCoordLocation, 2, GL_FLOAT, GL_FALSE,
+                         offsetof(ScreenRectVertex, tex_coord));
+    glVertexAttribBinding(PositionLocation, 0);
+    glVertexAttribBinding(TexCoordLocation, 0);
+    if (device.HasVertexBufferUnifiedMemory()) {
+        glBindVertexBuffer(0, 0, 0, sizeof(ScreenRectVertex));
+        glBufferAddressRangeNV(GL_VERTEX_ATTRIB_ARRAY_ADDRESS_NV, 0, vertex_buffer_address,
+                               sizeof(vertices));
+    } else {
+        glBindVertexBuffer(0, vertex_buffer.handle, 0, sizeof(ScreenRectVertex));
+    }
+
+    glBindSampler(0, sampler.handle);
+
+    // Update background color before drawing
+    glClearColor(Settings::values.bg_red.GetValue() / 255.0f,
+                 Settings::values.bg_green.GetValue() / 255.0f,
+                 Settings::values.bg_blue.GetValue() / 255.0f, 1.0f);
+
+    glClear(GL_COLOR_BUFFER_BIT);
+    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+}
+
+} // namespace OpenGL