1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
|
//
// Created by saintruler on 05.05.19.
//
#include "Canvas.h"
Canvas::Canvas(int width, int height, Point *points, int nPoints)
{
float vertices[] = {
// positions // colors // texture coords
1.f, 1.f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, // top right
1.f, -1.f, 0.0f, 0.0f, 1.0f, 0.0f, 1.0f, 0.0f, // bottom right
-1.f, -1.f, 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom left
-1.f, 1.f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f // top left
};
int indices[] = {
0, 1, 3, // first triangle
1, 2, 3 // second triangle
};
glGenVertexArrays(1, &VAO);
glGenBuffers(1, &VBO);
glGenBuffers(1, &EBO);
glBindVertexArray(VAO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
// position attribute
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
glEnableVertexAttribArray(0);
// color attribute
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
glEnableVertexAttribArray(1);
// texture coord attribute
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
glEnableVertexAttribArray(2);
this->width = width;
this->height = height;
this->nPoints = nPoints;
this->points = points;
canvas = (unsigned char*) malloc(width * height * 3);
glGenTextures(1, &texture);
}
void Canvas::SetPixel(int x, int y, Color color)
{
canvas[y * width * 3 + x * 3 + 0] = color.r;
canvas[y * width * 3 + x * 3 + 1] = color.g;
canvas[y * width * 3 + x * 3 + 2] = color.b;
UpdateTexture();
}
void Canvas::UpdateTexture()
{
// all upcoming GL_TEXTURE_2D operations now have effect on this texture object
glBindTexture(GL_TEXTURE_2D, texture);
// set texture wrapping to GL_REPEAT (default wrapping method)
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// set texture filtering parameters
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
generate_canvas(width, height, canvas, points, nPoints);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, width, 0, GL_RGB, GL_UNSIGNED_BYTE, canvas);
glGenerateMipmap(GL_TEXTURE_2D);
}
void Canvas::DrawTexture()
{
UpdateTexture();
glBindTexture(GL_TEXTURE_2D, texture);
shader.use();
glBindVertexArray(VAO);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
}
void Canvas::DeleteCanvas()
{
glDeleteVertexArrays(1, &VAO);
glDeleteBuffers(1, &VBO);
glDeleteBuffers(1, &EBO);
delete[] canvas;
}
|
