Render text with a C64 font!

[mandelwow.git] / text.rs

diff --git a/text.rs b/text.rs
new file mode 100644 (file)
index 0000000..c483846
--- /dev/null
+++ b/text.rs
@@ -0,0 +1,137 @@
+use cgmath::conv::array4x4;
+use cgmath::{Matrix4, One};
+use glium;
+use glium::{Surface, texture};
+use image;
+use std::io::Cursor;
+
+#[derive(Copy, Clone)]
+struct Vertex {
+    position: [f32; 2],
+    tex_coords: [f32; 2],
+}
+implement_vertex!(Vertex, position, tex_coords);
+
+pub struct Text<'a> {
+    tex: texture::CompressedSrgbTexture2d,
+    vertex_buffer: glium::VertexBuffer<Vertex>,
+    index_buffer: glium::IndexBuffer<u16>,
+    program: glium::Program,
+    params: glium::DrawParameters<'a>,
+    model: Matrix4<f32>,
+}
+
+impl<'a> Text<'a> {
+    pub fn new(display: &glium::Display) -> Text {
+        let image = image::load(Cursor::new(&include_bytes!("c64-font.png")[..]), image::PNG)
+            .unwrap()
+            .to_rgba();
+        let dimensions = image.dimensions();
+        let image =
+            glium::texture::RawImage2d::from_raw_rgba_reversed(image.into_raw(), dimensions);
+        let tex = glium::texture::CompressedSrgbTexture2d::new(display, image).unwrap();
+
+        // building the vertex buffer, which contains all the vertices that we will draw
+        let vertex_buffer = {
+            glium::VertexBuffer::new(
+                display,
+                &[
+                    Vertex {
+                        position: [-1.0, -1.0],
+                        tex_coords: [0.0, 0.0],
+                    },
+                    Vertex {
+                        position: [-1.0, 1.0],
+                        tex_coords: [0.0, 1.0],
+                    },
+                    Vertex {
+                        position: [1.0, 1.0],
+                        tex_coords: [1.0, 1.0],
+                    },
+                    Vertex {
+                        position: [1.0, -1.0],
+                        tex_coords: [1.0, 0.0],
+                    },
+                ],
+            ).unwrap()
+        };
+
+        let index_buffer = glium::IndexBuffer::new(
+            display,
+            glium::index::PrimitiveType::TriangleStrip,
+            &[1 as u16, 2, 0, 3],
+        ).unwrap();
+
+        // compiling shaders and linking them together
+        let program = program!(display,
+        140 => {
+            vertex: "
+                #version 140
+
+                uniform mat4 model;
+                uniform mat4 perspview;
+
+                in vec2 position;
+                in vec2 tex_coords;
+
+                out vec2 v_tex_coords;
+
+                void main() {
+                    gl_Position = perspview * model * vec4(position, 0.0, 1.0);
+                    // Characters are arranged in a 16x16 square.
+                    // Texture oordinates originate in the bottom-left corner.
+                    v_tex_coords = (tex_coords) / 16.0 + vec2(0. / 16., 15. / 16.);
+                }
+            ",
+
+            fragment: "
+                #version 140
+                uniform sampler2D tex;
+                in vec2 v_tex_coords;
+                out vec4 f_color;
+
+                void main() {
+                    f_color = texture(tex, v_tex_coords);
+                }
+            "
+        }).unwrap();
+
+        let params = glium::DrawParameters {
+            depth: glium::Depth {
+                test: glium::draw_parameters::DepthTest::IfLess,
+                write: true,
+                ..Default::default()
+            },
+            multisampling: true,
+            ..Default::default()
+        };
+
+        Text {
+            model: Matrix4::one(),
+            tex: tex,
+            vertex_buffer: vertex_buffer,
+            index_buffer: index_buffer,
+            program: program,
+            params: params,
+        }
+    }
+
+    pub fn draw(&self, frame: &mut glium::Frame, perspview: &[[f32; 4]; 4]) {
+        let uniforms = uniform! {
+            model: array4x4(self.model),
+            perspview: *perspview,
+            tex: self.tex.sampled()
+                //.minify_filter(glium::uniforms::MinifySamplerFilter::Nearest)
+                .magnify_filter(glium::uniforms::MagnifySamplerFilter::Nearest),
+        };
+        frame
+            .draw(
+                &self.vertex_buffer,
+                &self.index_buffer,
+                &self.program,
+                &uniforms,
+                &self.params,
+            )
+            .unwrap();
+    }
+}