Cleaned up UI renderer a little and added color parameter for quads (WIP).

assets/shaders/glsl/ui.frag

@@ -0,0 +1,24 @@
+#version 460
+
+layout(set = 2, binding = 0)
+uniform sampler2D u_texture;
+
+layout(set = 3, binding = 0)
+uniform Parameters
+{
+    vec4 u_color;
+};
+
+layout(location = 0)
+in vec2 i_texCoord;
+
+layout(location = 1)
+in vec4 i_color;
+
+layout(location = 0)
+out vec4 o_color;
+
+void main()
+{
+    o_color = texture(u_texture, i_texCoord) * i_color * u_color;
+}

assets/shaders/glsl/ui.vert

@@ -12,13 +12,20 @@ in vec2 i_position;
 layout(location = 1)
 in vec2 i_texCoord;
 
+layout(location = 2)
+in vec4 i_color;
+
 layout(location = 0)
 out vec2 o_texCoord;
 
+layout(location = 1)
+out vec4 o_color;
+
 void main()
 {
     vec2 relativePos = 2.0 * (i_position / u_windowSize) - vec2(1.0);
     relativePos.y *= -1.0;
     gl_Position = vec4(relativePos, 0.0, 1.0);
     o_texCoord = i_texCoord;
+    o_color = i_color;
 }

private/sdl_gpu_test/6_ui/ui/ui_renderer.cpp

@@ -1,8 +1,6 @@
 
 #include "./ui_renderer.hpp"
 
-#include <glm/vec4.hpp>
-
 namespace sdl_gpu_test::inline app6
 {
 namespace
@@ -25,7 +23,7 @@ void UIRenderer::init(Application& application)
         .stage = sdlpp::GPUShaderStage::VERTEX,
         .numUniformBuffers = 1
     });
-    const sdlpp::GPUShader fragmentShader = application.loadShader("shaders/glsl/color_from_texture.frag.spv", {
+    const sdlpp::GPUShader fragmentShader = application.loadShader("shaders/glsl/ui.frag.spv", {
         .format = sdlpp::GPUShaderFormat::SPIRV,
         .stage = sdlpp::GPUShaderStage::FRAGMENT,
         .numSamplers = 1,
@@ -64,6 +62,12 @@ void UIRenderer::init(Application& application)
             .bindingIndex = 0,
             .format = sdlpp::GPUVertexElementFormat::FLOAT2,
             .offset = offsetof(UIVertex, texcoord)
+        },
+        sdlpp::GPUVertexAttribute{
+            .location = 2,
+            .bindingIndex = 0,
+            .format = sdlpp::GPUVertexElementFormat::FLOAT4,
+            .offset = offsetof(UIVertex, color)
         }
     };
     mUIPipeline.create(device, {
@@ -78,45 +82,20 @@ void UIRenderer::init(Application& application)
         }
     });
 
-
+    // load the font map for rendering text
     const FontMap fontMap = loadFontMap(application.getFileSystem().getPath("fonts/symtext.fnt"));
-    const UVFontMap uvFontMap = makeUVFontMap({
+    mFontMap = makeUVFontMap({
         .original = &fontMap,
         .textureWidth = 256,
         .textureHeight = 256
     });
 
-    unsigned posX = 100;
-    const unsigned posY = 100;
-    for (const char chr : std::string_view("Dies ist ein Test-Text!"))
-    {
-        const UVFontMapEntry& entry = uvFontMap.entries[chr < 0 ? '_' : chr];
-        const UIVertex topLeft = {
-            .pos = {posX + entry.xOffset, posY + entry.yOffset},
-            .texcoord = {entry.uvX, entry.uvY}
-        };
-        const UIVertex bottomRight = {
-            .pos = {topLeft.pos.x + static_cast<float>(entry.width), topLeft.pos.y + static_cast<float>(entry.height)},
-            .texcoord = {entry.uvX + entry.uvWidth, entry.uvY + entry.uvHeight}
-        };
-        const UIVertex bottomLeft = {
-            .pos = {topLeft.pos.x, bottomRight.pos.y},
-            .texcoord = {topLeft.texcoord.x, bottomRight.texcoord.y}
-        };
-        const UIVertex topRight = {
-            .pos = {bottomRight.pos.x, topLeft.pos.y},
-            .texcoord = {bottomRight.texcoord.x, topLeft.texcoord.y}
-        };
-
-        mUIVertices.push_back(topLeft);
-        mUIVertices.push_back(bottomLeft);
-        mUIVertices.push_back(topRight);
-        mUIVertices.push_back(bottomRight);
-        mUIVertices.push_back(topRight);
-        mUIVertices.push_back(bottomLeft);
-
-        posX += entry.xAdvance;
-    }
+    // render some test text
+    drawText({
+        .x = 100,
+        .y = 100,
+        .text = "Test-Text!\nSecond line?"
+    });
 
     // create UI vertex buffer
     mUIVertexBuffer.create(device, {
@@ -164,4 +143,67 @@ void UIRenderer::render(const UIRendererRenderArgs& args)
     }
 }
 
+void UIRenderer::drawText(const DrawTextArgs& args)
+{
+    unsigned posX = args.x;
+    unsigned posY = args.y;
+    for (const char chr : args.text)
+    {
+        switch (chr)
+        {
+            case '\n':
+                posX = args.x;
+                posY += mFontMap.lineHeight;
+                break;
+            default:
+                posX += drawChar({
+                    .x = posX,
+                    .y = posY,
+                    .chr = chr
+                });
+                break;
+        }
+    }
+}
+
+unsigned UIRenderer::drawChar(const DrawCharArgs& args)
+{
+    const UVFontMapEntry& entry = mFontMap.entries[args.chr < 0 ? '_' : args.chr]; // TODO: more chars
+    const glm::vec2 topLeft = {args.x + entry.xOffset, args.y + entry.yOffset};
+    drawQuadInternal({
+        .topLeft = topLeft,
+        .bottomRight = {topLeft.x + static_cast<float>(entry.width), topLeft.y + static_cast<float>(entry.height)},
+        .uvTopLeft = {entry.uvX, entry.uvY},
+        .uvBottomRight = {entry.uvX + entry.uvWidth, entry.uvY + entry.uvHeight}
+    });
+
+    return entry.xAdvance;
+}
+
+void UIRenderer::drawQuadInternal(const DrawQuadInternalArgs& args)
+{
+    const UIVertex topLeft = {
+        .pos = args.topLeft,
+        .texcoord = args.uvTopLeft
+    };
+    const UIVertex bottomRight = {
+        .pos = args.bottomRight,
+        .texcoord = args.uvBottomRight
+    };
+    const UIVertex bottomLeft = {
+        .pos = {topLeft.pos.x, bottomRight.pos.y},
+        .texcoord = {topLeft.texcoord.x, bottomRight.texcoord.y}
+    };
+    const UIVertex topRight = {
+        .pos = {bottomRight.pos.x, topLeft.pos.y},
+        .texcoord = {bottomRight.texcoord.x, topLeft.texcoord.y}
+    };
+
+    mUIVertices.push_back(topLeft);
+    mUIVertices.push_back(bottomLeft);
+    mUIVertices.push_back(topRight);
+    mUIVertices.push_back(bottomRight);
+    mUIVertices.push_back(topRight);
+    mUIVertices.push_back(bottomLeft);
+}
 }

private/sdl_gpu_test/6_ui/ui/ui_renderer.hpp

@@ -5,6 +5,7 @@
 #define SDL_GPU_TEST_PRIVATE_SDL_GPU_TEST_6_UI_UI_UI_RENDERER_HPP_INCLUDED 1
 
 #include <glm/vec2.hpp>
+#include <glm/vec4.hpp>
 #include "../../application.hpp"
 #include "../../sdlpp/gpu.hpp"
 #include "../../util/font_map.hpp"
@@ -15,6 +16,21 @@ struct UIVertex
 {
     glm::vec2 pos;
     glm::vec2 texcoord;
+    glm::vec4 color = glm::vec4(1.f);
+};
+
+struct DrawTextArgs
+{
+    unsigned x = 0;
+    unsigned y = 0;
+    std::string_view text;
+};
+
+struct DrawCharArgs
+{
+    unsigned x = 0;
+    unsigned y = 0;
+    char chr;
 };
 
 struct UIRendererRenderArgs
@@ -38,6 +54,18 @@ private:
 public:
     void init(Application& application);
     void render(const UIRendererRenderArgs& args);
+
+    void drawText(const DrawTextArgs& args);
+    unsigned drawChar(const DrawCharArgs& args);
+private:
+    struct DrawQuadInternalArgs
+    {
+        glm::vec2 topLeft;
+        glm::vec2 bottomRight;
+        glm::vec2 uvTopLeft;
+        glm::vec2 uvBottomRight;
+    };
+    void drawQuadInternal(const DrawQuadInternalArgs& args);
 };
 } // namespace sdl_gpu_test::inline app6