add a rectangle shader

share/jes/shaders/rect.f.glsl

@@ -0,0 +1,11 @@
+#version 130
+
+/* Color */
+uniform vec4 color;
+
+out vec4 frag_color;
+
+void main(void)
+{
+    frag_color = color;
+}

share/jes/shaders/rect.v.glsl

@@ -0,0 +1,25 @@
+#version 130
+
+/* Viewport width and height */
+uniform ivec2 viewport_size;
+/* Position offset */
+uniform ivec2 position;
+/* Rectangle size */
+uniform ivec2 size;
+
+/* Vertex coordinates: x, y */
+in vec2 coords;
+
+/**
+ * Map coordinates such that:
+ * (0 .. viewport_size.[xy]) => (-1.0 .. 1.0)
+ */
+vec2 map_to_screen(vec2 position)
+{
+    return 2.0 * position / viewport_size - 1.0;
+}
+
+void main(void)
+{
+    gl_Position = vec4(map_to_screen(vec2(position) + coords * size), 0, 1);
+}

src/gui/Shaders/RectShader.cc

@@ -0,0 +1,18 @@
+#include "RectShader.h"
+#include "Runtime.h"
+
+RectShader::RectShader()
+{
+    std::string v_path = Runtime::find(Runtime::SHADER, "rect.v");
+    std::string f_path = Runtime::find(Runtime::SHADER, "rect.f");
+
+    m_program = glcxx::Program::create(
+            glcxx::Shader::create_from_file(GL_VERTEX_SHADER, v_path.c_str()),
+            glcxx::Shader::create_from_file(GL_FRAGMENT_SHADER, f_path.c_str()),
+            "coords", 0);
+
+    m_uniforms.viewport_size = m_program->get_uniform_location("viewport_size");
+    m_uniforms.color = m_program->get_uniform_location("color");
+    m_uniforms.position = m_program->get_uniform_location("position");
+    m_uniforms.size = m_program->get_uniform_location("size");
+}

src/gui/Shaders/RectShader.h

@@ -0,0 +1,46 @@
+#ifndef RECTSHADER_H
+#define RECTSHADER_H
+
+#include "glcxx.hpp"
+#include <memory>
+
+class RectShader
+{
+public:
+    RectShader();
+
+    void use() { m_program->use(); }
+
+    void set_viewport_size(int width, int height)
+    {
+        glUniform2i(m_uniforms.viewport_size, width, height);
+    }
+
+    void set_color(float r, float g, float b, float a)
+    {
+        glUniform4f(m_uniforms.color, r, g, b, a);
+    }
+
+    void set_position(int x, int y)
+    {
+        glUniform2i(m_uniforms.position, x, y);
+    }
+
+    void set_size(int x, int y)
+    {
+        glUniform2i(m_uniforms.size, x, y);
+    }
+
+protected:
+    std::shared_ptr<glcxx::Program> m_program;
+
+    struct
+    {
+        GLint viewport_size;
+        GLint color;
+        GLint position;
+        GLint size;
+    } m_uniforms;
+};
+
+#endif

src/gui/Window.cc

@@ -118,6 +118,7 @@ bool Window::create(std::shared_ptr<Buffer> buffer)
     m_shaders.text->set_color(1.0, 1.0, 1.0, 1.0);
 
     m_shaders.flat = std::make_shared<FlatShader>();
+    m_shaders.rect = std::make_shared<RectShader>();
 
     GLint cursor_bounds[] = {0, 0,
         m_font.get_advance(), 0,
@@ -130,6 +131,18 @@ bool Window::create(std::shared_ptr<Buffer> buffer)
     glEnableVertexAttribArray(0);
     glVertexAttribPointer(0, 2, GL_INT, GL_FALSE, 0, 0);
 
+    GLint rect_coords[] = {
+        0, 0,
+        1, 0,
+        1, 1,
+        0, 1};
+    m_rect_array = glcxx::Array::create();
+    m_rect_array->bind();
+    m_rect_buffer = glcxx::Buffer::create(GL_ARRAY_BUFFER, GL_STATIC_DRAW,
+            rect_coords, sizeof(rect_coords));
+    glEnableVertexAttribArray(0);
+    glVertexAttribPointer(0, 2, GL_INT, GL_FALSE, 0, 0);
+
     m_buffer = buffer;
     m_cursor = m_buffer->piece_table->add_cursor();
     m_start_piece = m_buffer->piece_table->start_piece->next;
@@ -430,6 +443,8 @@ void Window::resize()
     m_shaders.text->set_viewport_size(m_width, m_height);
     m_shaders.flat->use();
     m_shaders.flat->set_viewport_size(m_width, m_height);
+    m_shaders.rect->use();
+    m_shaders.rect->set_viewport_size(m_width, m_height);
     m_columns = m_width / m_font.get_advance();
     if (m_columns < 1)
         m_columns = 1;
@@ -474,3 +489,13 @@ void Window::colrow_to_xy(int col, int row, int * x, int * y)
     *x = col * m_font.get_advance();
     *y = m_height - (row + 1) * m_font.get_line_height();
 }
+
+void Window::draw_rect(int x, int y, int width, int height, float r, float g, float b, float a)
+{
+    m_rect_array->bind();
+    m_shaders.rect->use();
+    m_shaders.rect->set_color(r, g, b, a);
+    m_shaders.rect->set_position(x, y);
+    m_shaders.rect->set_size(width, height);
+    glDrawArrays(GL_TRIANGLE_FAN, 0, 4);
+}

src/gui/Window.h

@@ -5,6 +5,7 @@
 #include <SDL.h>
 #include "TextShader.h"
 #include "FlatShader.h"
+#include "RectShader.h"
 #include "Font.h"
 #include "Buffer.h"
 #include "glcxx.hpp"
@@ -38,6 +39,7 @@ protected:
     void draw_text();
     void draw_character(int screen_column, int screen_row, uint32_t character);
     void update_cursor_row(int cursor_row);
+    void draw_rect(int x, int y, int width, int height, float r, float g, float b, float a);
 
     SDL_Window * m_window;
     bool m_exit_requested;
@@ -47,6 +49,7 @@ protected:
     {
         std::shared_ptr<TextShader> text;
         std::shared_ptr<FlatShader> flat;
+        std::shared_ptr<RectShader> rect;
     } m_shaders;
 
     Font m_font;
@@ -60,6 +63,8 @@ protected:
 
     std::shared_ptr<glcxx::Array> m_cursor_array;
     std::shared_ptr<glcxx::Buffer> m_cursor_buffer;
+    std::shared_ptr<glcxx::Array> m_rect_array;
+    std::shared_ptr<glcxx::Buffer> m_rect_buffer;
 
     std::shared_ptr<PieceTable::Cursor> m_cursor;