{

static const char *vertexCode =

"uniform vec2 scale;\n"

"uniform vec2 center;\n"

"uniform vec2 size;\n"

"in vec2 vert;\n"

"void main() {\n"

" gl_Position = vec4((center + vert * size) * scale, 0, 1);\n"

"}\n";

static const char *fragmentCode =

"uniform vec4 color = vec4(1, 1, 1, 1);\n"

"out vec4 finalColor;\n"

"void main() {\n"

" finalColor = color;\n"

"}\n";

shader = Shader(vertexCode, fragmentCode);

scaleI = shader.Uniform("scale");

centerI = shader.Uniform("center");

sizeI = shader.Uniform("size");

colorI = shader.Uniform("color");

// Generate the vertex data for drawing sprites.

glGenVertexArrays(1, &vao);

glBindVertexArray(vao);

glGenBuffers(1, &vbo);

glBindBuffer(GL_ARRAY_BUFFER, vbo);

GLfloat vertexData[] = {

-.5f, -.5f,

.5f, -.5f,

-.5f, .5f,

.5f, .5f

};

glBufferData(GL_ARRAY_BUFFER, sizeof(vertexData), vertexData, GL_STATIC_DRAW);

glEnableVertexAttribArray(shader.Attrib("vert"));

glVertexAttribPointer(shader.Attrib("vert"), 2, GL_FLOAT, GL_FALSE, 2 * sizeof(GLfloat), nullptr);

// unbind the VBO and VAO

glBindBuffer(GL_ARRAY_BUFFER, 0);

glBindVertexArray(0);

{

if(!shader.Object())

throw runtime_error("FillShader: Draw() called before Init().");

glUseProgram(shader.Object());

glBindVertexArray(vao);

GLfloat scale[2] = {2.f / Screen::Width(), -2.f / Screen::Height()};

glUniform2fv(scaleI, 1, scale);

GLfloat centerV[2] = {static_cast<float>(center.X()), static_cast<float>(center.Y())};

glUniform2fv(centerI, 1, centerV);

GLfloat sizeV[2] = {static_cast<float>(size.X()), static_cast<float>(size.Y())};

glUniform2fv(sizeI, 1, sizeV);

glUniform4fv(colorI, 1, color.Get());

glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

glBindVertexArray(0);

glUseProgram(0);