From 058ec6d26eaa2ed0114e8bb4f0fb3a709d4ea77b Mon Sep 17 00:00:00 2001
From: Swung0x48 <swung0x48@outlook.com>
Date: Tue, 17 Feb 2026 11:33:27 +0800
Subject: [PATCH] [Feat] (MG_Backend/DirectVulkan): implement vao/vbo binding

---
 .../Renderer/VertexInputStateFactory.cpp      | 32 +++++++++++++--
 .../MG_Test/Backend/DirectVulkan/TestExec.cpp | 41 ++++++++++++++-----
 2 files changed, 60 insertions(+), 13 deletions(-)

diff --git a/MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp b/MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp
index d3affbea..c98d29df 100644
--- a/MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp
+++ b/MobileGL/MG_Backend/DirectVulkan/Renderer/VertexInputStateFactory.cpp
@@ -46,6 +46,11 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         }
 
         VertexInputStateBuilder builder;
+        const void* sourceBuffer = nullptr;
+        Uint32 sourceStride = 0;
+        VkVertexInputRate sourceInputRate = VK_VERTEX_INPUT_RATE_VERTEX;
+        Bool hasBinding = false;
+
         for (Uint32 location = 0; location < MG_State::GLState::VertexArrayObject::MAX_VERTEX_ATTRIBS; ++location) {
             const auto& attr = vao.GetAttribute(location);
             if (!attr.Enabled || !attr.Buffer) {
@@ -72,9 +77,30 @@ namespace MobileGL::MG_Backend::DirectVulkan {
             const VkVertexInputRate inputRate =
                 (attr.Divisor == 0) ? VK_VERTEX_INPUT_RATE_VERTEX : VK_VERTEX_INPUT_RATE_INSTANCE;
 
-            builder
-                .AddBinding(location, stride, inputRate)
-                .AddAttribute(location, location, vkFormat, static_cast<Uint32>(attr.Offset));
+            if (!hasBinding) {
+                sourceBuffer = attr.Buffer.get();
+                sourceStride = stride;
+                sourceInputRate = inputRate;
+                builder.AddBinding(0, sourceStride, sourceInputRate);
+                hasBinding = true;
+            } else {
+                if (attr.Buffer.get() != sourceBuffer) {
+                    MGLOG_W("Skipping vertex attribute at location %u: only single-buffer vertex input is supported for now",
+                            location);
+                    continue;
+                }
+                if (stride != sourceStride) {
+                    MGLOG_W("Skipping vertex attribute at location %u: stride mismatch (%u vs %u) for single-binding path",
+                            location, stride, sourceStride);
+                    continue;
+                }
+                if (inputRate != sourceInputRate) {
+                    MGLOG_W("Skipping vertex attribute at location %u: input-rate mismatch for single-binding path", location);
+                    continue;
+                }
+            }
+
+            builder.AddAttribute(location, 0, vkFormat, static_cast<Uint32>(attr.Offset));
         }
 
         const auto& state = builder.Build();
diff --git a/MobileGL/MG_Test/Backend/DirectVulkan/TestExec.cpp b/MobileGL/MG_Test/Backend/DirectVulkan/TestExec.cpp
index 6bd6740c..e288f32f 100644
--- a/MobileGL/MG_Test/Backend/DirectVulkan/TestExec.cpp
+++ b/MobileGL/MG_Test/Backend/DirectVulkan/TestExec.cpp
@@ -134,26 +134,46 @@ int main() {
     glGenVertexArrays(1, &vao);
     glBindVertexArray(vao);
 
-    static constexpr GLushort kQuadIndices[] = {0, 1, 2, 2, 3, 0};
+    static constexpr GLfloat kQuadVertices[] = {
+        // triangle 1
+        -0.6f, -0.6f, 1.0f, 0.0f, 0.0f,
+         0.6f, -0.6f, 0.0f, 1.0f, 0.0f,
+         0.6f,  0.6f, 0.0f, 0.0f, 1.0f,
+        // triangle 2
+         0.6f,  0.6f, 1.0f, 0.0f, 0.0f,
+        -0.6f,  0.6f, 0.0f, 1.0f, 0.0f,
+        -0.6f, -0.6f, 0.0f, 0.0f, 1.0f
+    };
+
+    GLuint vbo = 0;
+    glGenBuffers(1, &vbo);
+    glBindBuffer(GL_ARRAY_BUFFER, vbo);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(kQuadVertices), kQuadVertices, GL_STATIC_DRAW);
+    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, static_cast<GLsizei>(5 * sizeof(GLfloat)), nullptr);
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, static_cast<GLsizei>(5 * sizeof(GLfloat)),
+                          reinterpret_cast<const void*>(2 * sizeof(GLfloat)));
+    glEnableVertexAttribArray(1);
+
+    static constexpr GLushort kQuadIndices[] = {0, 1, 2, 3, 4, 5};
     GLuint ebo = 0;
     glGenBuffers(1, &ebo);
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
     glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(kQuadIndices), kQuadIndices, GL_STATIC_DRAW);
 
-    static constexpr const char* kVertexShaderSource = R"(#version 330 core
+static constexpr const char* kVertexShaderSource = R"(#version 330 core
+layout(location = 0) in vec2 aPos;
+layout(location = 1) in vec3 aColor;
+out vec3 vColor;
 void main() {
-    const vec2 kPositions[4] = vec2[](
-        vec2(-0.6, -0.6),
-        vec2( 0.6, -0.6),
-        vec2( 0.6,  0.6),
-        vec2(-0.6,  0.6)
-    );
-    gl_Position = vec4(kPositions[gl_VertexID], 0.0, 1.0);
+    gl_Position = vec4(aPos, 0.0, 1.0);
+    vColor = aColor;
 })";
     static constexpr const char* kFragmentShaderSource = R"(#version 330 core
+in vec3 vColor;
 layout(location = 0) out vec4 outColor;
 void main() {
-    outColor = vec4(0.95, 0.85, 0.2, 1.0);
+    outColor = vec4(vColor, 1.0);
 })";
 
     const GLuint vs = glCreateShader(GL_VERTEX_SHADER);
@@ -199,6 +219,7 @@ void main() {
     }
 
     glDeleteProgram(program);
+    glDeleteBuffers(1, &vbo);
     glDeleteBuffers(1, &ebo);
     glDeleteVertexArrays(1, &vao);