✨ Canvas rotation and translation.

assets/shaders/canvas_vertex.glsl

@@ -8,9 +8,10 @@ out vec4 _color;
 out vec2 _tex_coord;
 
 uniform mat4 proj;
+uniform mat4 model;
 
 void main() {
-  gl_Position = proj * vec4(pos, 1.0);
+  gl_Position = proj * model * vec4(pos, 1.0);
   _color = color;
   _tex_coord = tex_coord;
 }

src/arena/Arena.cpp

@@ -11,12 +11,14 @@ namespace rid
     tex->load(RID_DATADIR / "assets" / "images" / "walk_0.png");
     m_canvas->set_texture(std::move(tex));
 
-    m_canvas->draw_tex(glm::vec2 {512.0f, 512.0f},
+    m_canvas->draw_tex(glm::vec2 {0.0f, 0.0f},
                        glm::vec2 {96.0f, 96.0f},
                        glm::vec4 {1.0f, 1.0f, 1.0f, 1.0f},
                        glm::vec2 {0.f, 0.0f},
                        glm::vec2 {32.0f, 32.0f});
 
+    m_canvas->move(glm::vec2 {512.f, 512.f});
+
   }
 
   /*virtual*/ Arena::~Arena()

src/gfx/Canvas.cpp

@@ -21,6 +21,16 @@ namespace rid
     glDeleteBuffers(1, &m_vbo);
   }
 
+  void Canvas::move(glm::vec2 pos)
+  {
+    m_pos += pos;
+  }
+
+  void Canvas::rotate(float rad)
+  {
+    m_angle += rad;
+  }
+
   void Canvas::set_texture(std::unique_ptr<Texture> texture)
   {
     m_shaders->use();
@@ -90,6 +100,11 @@ namespace rid
   {
     use();
     m_shaders->set_mat4("proj", transform);
+
+    auto rot = glm::rotate(glm::mat4 {1.0f}, m_angle, glm::vec3 {0.f, 0.f, 1.f});
+    auto loc = glm::translate(glm::mat4 {1.0f}, glm::vec3 {m_pos.x, m_pos.y, 0.f});
+
+    m_shaders->set_mat4("model", loc * rot);
     glDrawArrays(GL_TRIANGLES, 0, m_vertices.size());
   }
 

src/gfx/Canvas.hpp

@@ -20,6 +20,9 @@ namespace rid
     explicit Canvas();
     virtual ~Canvas();
 
+    void move(glm::vec2 pos);
+    void rotate(float rad);
+
     void set_texture(std::unique_ptr<Texture> texture);
 
     // Draw stuff
@@ -37,6 +40,9 @@ namespace rid
     std::unique_ptr<Shaders> m_shaders;
     std::vector<Vertex> m_vertices;
     std::unique_ptr<Texture> m_texture;
+    glm::vec2 m_pos {0.f};
+    float m_angle = 0.f;
+
     GLuint m_vao;
     GLuint m_vbo;