[英]Cannot get texture to appear using OpenGL
在使用opengl 4.5的Windows計算機上,我似乎無法使紋理顯示在屏幕上。 我收到的只是一個黑屏。 對於我的代碼,我首先開發了一個小的Vector類來容納所有頂點屬性信息:
Vector3D.h
struct Position
{
Position();
Position(float x, float y, float z);
float x;
float y;
float z;
};
Position::Position()
{}
Position::Position(float x, float y, float z) :
x(x), y(y), z(z)
{}
struct Color
{
GLubyte r;
GLubyte g;
GLubyte b;
GLubyte a;
};
struct TextureCoordinate
{
float u;
float v;
};
struct Vector3D
{
Vector3D();
Vector3D(float x, float y, float z);
Position position;
Color color;
TextureCoordinate textCoordinate;
void setUV(float u, float v);
};
Vector3D::Vector3D()
{}
Vector3D::Vector3D(float x, float y, float z) :
position(x, y, z)
{}
void Vector3D::setUV(float u, float v)
{
this->textCoordinate.u = u;
this->textCoordinate.v = v;
}
然后,我有了一個Sprite類,通過它我可以使用Init()函數初始化頂點屬性:
雪碧
void Sprite::Init(float x, float y, float width, float height)
{
this->x = x;
this->y = y;
this->width = width;
this->height = height;
if (vboID == 0)
glGenBuffers(1, &vboID);
Vector3D vertexData[6]{
Vector3D {x + width, y + height, 1.0f},
Vector3D {x, y + height, 1.0f },
Vector3D {x, y, 1.0f},
Vector3D {x, y, 1.0f},
Vector3D {x + width, y, 1.0f},
Vector3D {x + width, y + height, 1.0f},
};
for (int i = 0; i < 6; ++i)
{
vertexData[i].color.r = 0;
vertexData[i].color.g = 155;
vertexData[i].color.b = 200;
};
vertexData[0].setUV(1.0f, 1.0f);
vertexData[1].setUV(0.0f, 1.0f);
vertexData[2].setUV(0.0f, 0.0f);
vertexData[3].setUV(0.0f, 0.0f);
vertexData[4].setUV(1.0f, 0.0f);
vertexData[5].setUV(1.0f, 1.0f);
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertexData), vertexData, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
然后,我在sprite類中具有了draw函數,該函數顯然會重新綁定以更正VBO並繪制圖像:
雪碧
void Sprite::Draw()
{
glBindBuffer(GL_ARRAY_BUFFER, vboID);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vector3D), (void*)offsetof(Vector3D, position));
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vector3D), (void*)offsetof(Vector3D, textCoordinate));
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
最后,我在這里的主函數中調用以上所有內容(我也在使用SDL和圖像加載庫stb):
main.cpp
int main(int agrc, char** argv)
{
window.Initialize();
playerSprite.Init(-1.0f, -1.0f, 1.0f, 1.0f);
GameState gamestate{ GameState::PLAY };
SDL_Event evnt;
int32 x, y, currentChannels;
int32 forceChannels = 4;
uchar8* imageData = 0;
imageData = stbi_load("CharImage.png", &x, &y, ¤tChannels, forceChannels);
if (imageData == nullptr)
{
LOG("ERROR: Could not load image file!");
};
GLuint texture;
glGenTextures(1, &texture);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, texture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, x, y, 0, GL_RGBA, GL_UNSIGNED_BYTE, imageData);
glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTextureParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
Blz::OpenGL::ShaderProgram colorShaderProgram;
colorShaderProgram.Compile();
colorShaderProgram.Link();
colorShaderProgram.Bind();
glEnableVertexAttribArray(0);
glEnableVertexAttribArray(1);
while (gamestate != GameState::EXIT)
{
unsigned int startTime = SDL_GetTicks();
//Game Logic Update
while (SDL_PollEvent(&evnt))
{
switch (evnt.type)
{
case SDL_QUIT:
gamestate = GameState::EXIT;
default:
break;
}
}
window.ClearBuffers();
playerSprite.Draw();
window.SwapBuffers();
}
return 0;
}
另外,這是我的着色器:
頂點着色器
#version 430
layout(location=0) in vec3 vertexPosition;
layout(location=1) in vec2 textCoord;
out vec2 TextureCoord;
void main()
{
gl_Position = vec4(vertexPosition, 1.0f);
TextureCoord = textCoord;
};
片段着色器
#version 430
out vec4 daColor;
in vec2 TextureCoord;
uniform sampler2D basicTexture;
void main()
{
vec4 texel = texture(basicTexture, TextureCoord);
daColor = texel;
};
我希望像這樣的時代,跨平台圖形編程能夠有更好的選擇,因為openGL確實是一團糟。 我的圖片未顯示的原因是因為我使用以下命令設置了參數:
glTextureParameteri()
而不是表面上正確的:
glTexParameteri()
.....................
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