all important components are rewired and can be used

examples/simple/main.cpp

@@ -18,36 +18,56 @@
 
 void setup_shaders(paradiso::Shader& shader) {
     const auto unlit_v = R"(
-#version 330 core
+#version 400 core
 
 layout (location = 0) in vec3 vertices;
 layout (location = 1) in vec3 normals;
 layout (location = 2) in vec2 texture_coords;
 
+// pivot der sprite
 uniform vec2 pivot = vec2( 0.0, 0.0 );
+// scale 
+uniform vec2 scale = vec2( 1.0, 1.0 );
+// rotation
+uniform float rotation = 0.2;
 
-vec4 pivot_3d = vec4( pivot , 0.0, 1.0 );
+// wir sind natuerlich in homogenenen 3D Koordinaten unterwegs
+mat4 mm = mat4(
+    vec4( scale.x, 0.0, 0.0, 0.0),
+    vec4( 0.0, scale.y, 0.0, 0.0),
+    vec4( 0.0, 0.0, 1.0, 0.0),
+    vec4( pivot, 0.0, 1.0)
+);
 
-out vec2 tex_c;
+float sir = sin(rotation);
+float cor = cos(rotation);
+
+mat4 mr = mat4(
+    vec4( cor, sir, 0.0, 0.0),
+    vec4(-sir, cor, 0.0, 0.0),
+    vec4( 0.0, 0.0, 1.0, 0.0),
+    vec4( 0.0, 0.0, 0.0, 1.0)
+    );
+
+out vec2 tex_c; // das hier reicht die texturkoordinaten durch
 
 void main() {
-    tex_c = texture_coords;
-    gl_Position = vec4(vertices, 1.0) + pivot_3d;
+    tex_c = texture_coords; // umstaendlich aber notwendig
+    gl_Position = mm * mr * vec4(vertices, 1.0); // unsere eigentliche shader position
 }
 )";
 
     const auto unlit_f = R"(
-#version 330 core
+#version 400 core
 
-uniform vec4 color = vec4(1.0, 0.0, 0.0, 1.0);
-uniform sampler2D tex_color;
+uniform sampler2D tex_color; // hier ist unsere sprite textur (bitmap)
 
-in vec2 tex_c;
+in vec2 tex_c; // da sind die texturkoordinaten wieder
 
-out vec4 frag_color;
+out vec4 frag_color; // das hier wird der output (pixelwert/fragment)
 
 void main() {
-    frag_color = texture(tex_color,tex_c); // *  color;
+    frag_color = texture(tex_color,tex_c);
 })";
 
     shader.set_source(paradiso::Shader::Type::Vertex, unlit_v);
@@ -111,6 +131,10 @@ auto main() -> int {
                 sprite.pivot.x() -= 0.1f;
             } else if (key == 'D') {
                 sprite.pivot.x() += 0.1f;
+            } else if (key == 'P') {
+                sprite.scale *= 0.9;
+            } else if (key == 'R') {
+                sprite.rotation += 0.1;
             }
         });
 
@@ -136,8 +160,10 @@ auto main() -> int {
         // hier wird das eigentliche löschen des vorherigen Inhalts ausgelöst
         ctx.clear();
 
-        // wir setzen den pivot der sprite über den shader
+        // wir setzen die daten der sprite über den shader
         shader.set_uniform("pivot", sprite.pivot);
+        shader.set_uniform("scale", sprite.scale);
+        shader.set_uniform("rotation", sprite.rotation);
 
         // Ein `renderer` kann nur mit einer Sprite verwendet werden!
         // Aber ein Shader kann man für mehrere Sprite-Renderer Kombis verwenden

src/lib/include/paradiso/matrixbase.hpp

@@ -67,12 +67,15 @@ template <typename Scalar, typename Derived> struct MatrixBase {
         return derived();
     }
 
-    static constexpr Derived zero() noexcept {
+    static constexpr Derived
+    all(const std::convertible_to<Scalar> auto& v) noexcept {
         Derived d;
-        d.fill(0);
+        d.fill(v);
         return d;
     }
 
+    static constexpr Derived zero() noexcept { return Derived::all(Scalar{0}); }
+
     constexpr Scalar squared_norm() const { return dot(*this, *this); }
 
     constexpr Scalar norm() const { return std::sqrt(squared_norm()); }

src/lib/include/paradiso/shader.hpp

@@ -51,19 +51,18 @@ struct Shader final {
 
     void use() const;
 
-
-
-    Shader& set_uniform_at_location(int location,
-                                    float v); //!< sets a float in a shader
-    Shader&
-    set_uniform_at_location(int location,
-                            uint32_t v); //!< sets a 32bit unsigned in a shader
     const Shader&
     set_uniform_at_location(int location,
+                            float v) const; //!< sets a float in a shader
+    const Shader& set_uniform_at_location(
+        int location,
+        uint32_t v) const; //!< sets a 32bit unsigned in a shader
+    const Shader& set_uniform_at_location(
+        int location,
         int32_t v) const; //!< sets a 32bit signed in a shader
 
-    const Shader&
-    set_uniform_at_location(int location,
+    const Shader& set_uniform_at_location(
+        int location,
         const Vector2<float>& v) const; //!< sets a 2D float vector
     /**
      * @brief retrieves the position of a uniform
@@ -91,8 +90,8 @@ struct Shader final {
     }
 
     using uniform_t =
-        std::variant<bool, int, float,
-                     double ,Vector2<float>/*vector3f,vector4f,matrix4x4f*/>;
+        std::variant<bool, int, float, double,
+                     Vector2<float> /*vector3f,vector4f,matrix4x4f*/>;
     using uniform_entry_t = std::tuple<std::string, uniform_t, int>;
 
     using uniform_cache_t = std::vector<uniform_entry_t>;

src/lib/include/paradiso/sprite.hpp

@@ -23,8 +23,8 @@
 #ifndef PARADISO_SPRITE_HPP
 #define PARADISO_SPRITE_HPP
 
-#include <paradiso/globals.hpp>
 #include <paradiso/bitmap.hpp>
+#include <paradiso/globals.hpp>
 #include <paradiso/matrix.hpp>
 #include <paradiso/vector.hpp>
 
@@ -32,13 +32,15 @@ namespace paradiso {
 
 /**
  * @brief simple sprite handler
-*/
+ */
 struct Sprite final {
     using ChangeCountType = std::uint64_t;
 
     Bitmap bitmap{}; //!< associated bitmap
 
     Vector2<float> pivot{Vector2<float>::zero()}; //!< center point
+    Vector2<float> scale{Vector2<float>::all(1)}; //!< scale
+    float rotation{0.0f};                         //!< rotation
 
     // 0      3    |      y
     // +------+    |      ^
@@ -49,17 +51,20 @@ struct Sprite final {
 
     std::array<std::uint32_t, 6> indices{0, 1, 2, 0, 2, 3}; //!< topology
 
-    std::array<Vector3<float>, 4> vertices{ //!< geometry
+    std::array<Vector3<float>, 4> vertices{
+        //!< geometry
         Vector3<float>::make(-1.0f, +1.0f, 0.0f),
         Vector3<float>::make(-1.0f, -1.0f, 0.0f),
         Vector3<float>::make(+1.0f, -1.0f, 0.0f),
         Vector3<float>::make(+1.0f, +1.0f, 0.0f)};
 
-    std::array<Vector3<float>, 4> normals{ //!< normals
+    std::array<Vector3<float>, 4> normals{
+        //!< normals
         Vector3<float>::z_axis(), Vector3<float>::z_axis(),
         Vector3<float>::z_axis(), Vector3<float>::z_axis()};
 
-    std::array<Vector2<float>, 4> texture_coordinates{ //!< UV coordinates
+    std::array<Vector2<float>, 4> texture_coordinates{
+        //!< UV coordinates
         Vector2<float>::make(0.0f, 0.0f), Vector2<float>::make(1.0f, 0.0f),
         Vector2<float>::make(1.0f, 1.0f), Vector2<float>::make(0.0f, 1.0f)};
 

src/lib/src/shader.cpp

@@ -199,12 +199,12 @@ Shader::~Shader() {}
 
 bool Shader::ready() const { return impl_->is_valid(); }
 
-Shader& Shader::set_uniform_at_location(int location, float v) {
+const Shader& Shader::set_uniform_at_location(int location, float v) const {
     impl_->bind(location, v);
     return *this;
 }
 
-Shader& Shader::set_uniform_at_location(int location, uint32_t v) {
+const Shader& Shader::set_uniform_at_location(int location, uint32_t v) const {
     impl_->bind(location, v);
     return *this;
 }
@@ -214,8 +214,8 @@ const Shader& Shader::set_uniform_at_location(int location, int32_t v) const {
     return *this;
 }
 
-const Shader &Shader::set_uniform_at_location(int location, Vector2<float> const &v) const
-{
+const Shader& Shader::set_uniform_at_location(int location,
+                                              Vector2<float> const& v) const {
     impl_->bind(location, v);
     return *this;
 }