love-demo2/src/pixel_line_art.cpp

139 lines
3.5 KiB
C++

#include "glad/gl.h"
#include "directxmath/directxmath.h"
#include <stdio.h>
#include "opengl.h"
#include "window.h"
#include "pixel_line_art.h"
extern unsigned int quad_index_buffer;
namespace pixel_line_art {
struct layout {
struct {
unsigned int position;
} attribute;
struct {
unsigned int transform;
unsigned int base_color;
} uniform;
};
const layout layout = {
.attribute = {
.position = 0,
},
.uniform = {
.transform = 0,
.base_color = 1,
},
};
static unsigned int program;
static unsigned int vertex_array_object;
static unsigned int per_vertex_buffer;
static int const per_vertex_size = (sizeof (float)) * 2;
static void load_program()
{
program = compile_from_files("shader/pixel_line_art.vert",
nullptr,
"shader/pixel_line_art.frag");
}
static void load_vertex_attributes()
{
glGenVertexArrays(1, &vertex_array_object);
glBindVertexArray(vertex_array_object);
glVertexBindingDivisor(0, 0);
glEnableVertexAttribArray(layout.attribute.position);
glVertexAttribFormat(layout.attribute.position, 2, GL_FLOAT, GL_FALSE, 0);
glVertexAttribBinding(layout.attribute.position, 0);
glBindVertexArray(0);
}
static void load_per_vertex_buffer(int x1, int y1, int x2, int y2)
{
float vertex_data[] = {
(float)x1, (float)y1, (float)x2, (float)y2,
};
int vertex_data_size = (sizeof (vertex_data));
glBindBuffer(GL_ARRAY_BUFFER, per_vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, vertex_data_size, vertex_data, GL_DYNAMIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
static void load_per_vertex_buffer2(int x1, int y1, int x2, int y2,
int x3, int y3, int x4, int y4)
{
float vertex_data[] = {
(float)x1, (float)y1, (float)x2, (float)y2,
(float)x3, (float)y3, (float)x4, (float)y4,
};
int vertex_data_size = (sizeof (vertex_data));
glBindBuffer(GL_ARRAY_BUFFER, per_vertex_buffer);
glBufferData(GL_ARRAY_BUFFER, vertex_data_size, vertex_data, GL_DYNAMIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
void load()
{
load_program();
load_vertex_attributes();
glGenBuffers(1, &per_vertex_buffer);
}
static void set_transform(XMMATRIX const & transform)
{
XMFLOAT4X4 float_transform;
XMStoreFloat4x4(&float_transform, transform);
glUniformMatrix4fv(layout.uniform.transform, 1, false, (float *)&float_transform);
}
void draw_line_quad_start()
{
glUseProgram(program);
glBlendFunc(GL_ONE, GL_ZERO);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_ALWAYS);
glBindVertexArray(vertex_array_object);
glBindVertexBuffer(0, per_vertex_buffer, 0, per_vertex_size);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, quad_index_buffer);
XMMATRIX transform
= XMMatrixScaling(2.0f / window::width, -2.0f / window::height, 0)
* XMMatrixTranslation(-1, 1, 0);
set_transform(transform);
}
void draw_line(int x1, int y1, int x2, int y2)
{
load_per_vertex_buffer(x1, y1, x2, y2);
glDrawArrays(GL_LINES, 0, 2);
}
void draw_quad(int x1, int y1, int x2, int y2,
int x3, int y3, int x4, int y4)
{
load_per_vertex_buffer2(x1, y1, x2, y2,
x3, y3, x4, y4);
glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_BYTE, (void *)0);
}
void draw_set_color(float r, float g, float b)
{
glUniform3f(layout.uniform.base_color, r, g, b);
}
}