c – 如何让纹理在OpenGL中工作？

我正在使用http://arcsynthesis.org/gltut/上的教程来学习OpenGL,这是必需的,我必须使用它.大多数情况下,我想将教程15中的纹理应用到教程7中的对象(使用UBO的世界).

现在,似乎纹理仅在打开mipmap时才起作用.这有一个缺点：使用的唯一mipmap是索引为零的那个,这是1色的1×1像素.我尝试将mipmap的最低级别设置得更高或完全关闭mipmap,但即使这样也无法解决问题,因为这样一切都会变成黑色.现在我将列出我的程序中最重要的部分

编辑：我想我会添加更多细节……

顶点着色器有这样的东西：

#version 330

layout(location = 0) in vec4 position;
layout(location = 1) in vec4 color;
layout(location = 2) in vec3 normal;
//Added these later 
layout(location = 5) in vec2 texCoord;
out vec2 colorCoord;

smooth out vec4 interpColor;
out vec3 vertexNormal;
out vec3 modelSpacePosition;
out vec3 cameraSpacePosition;

uniform mat4 worldToCameraMatrix;
uniform mat4 modelToWorldMatrix;
uniform mat3 normalModelToCameraMatrix;
uniform vec3 dirToLight;
uniform vec4 lightIntensity;
uniform vec4 ambientIntensity;
uniform vec4 baseColor;

uniform mat4 cameraToClipMatrix;

void main()
{
vertexNormal = normal;
vec3 normCamSpace = normalize(normalModelToCameraMatrix * vertexNormal);
cameraSpacePosition = normCamSpace;

float cosAngIncidence = dot(normCamSpace, dirToLight);
cosAngIncidence = clamp(cosAngIncidence, 0, 1);
modelSpacePosition.x = position.x;
modelSpacePosition.y = position.y;
modelSpacePosition.z = position.z;

vec4 temp = modelToWorldMatrix * position;
temp = worldToCameraMatrix * temp;
gl_Position = cameraToClipMatrix * temp;

interpColor = ((lightIntensity * cosAngIncidence) + (ambientIntensity)) * baseColor;
colorCoord= texCoord ;
}

片段着色器如下：

#version 330
in vec3 vertexNormal;
in vec3 modelSpacePosition;

smooth in vec4 interpColor;

uniform vec3 modelSpaceLightPos;
uniform vec4 lightIntensity2;
uniform vec4 ambientIntensity2;

out vec4 outputColor;

//Added later
in vec2 colorCoord;
uniform sampler2D colorTexture;


void main()
{
vec3 lightDir2 = normalize(modelSpacePosition - modelSpaceLightPos);

float cosAngIncidence2 = dot(normalize(vertexNormal), lightDir2);
cosAngIncidence2 = clamp(cosAngIncidence2, 0,  1);

float light2DistanceSqr = dot(modelSpacePosition - modelSpaceLightPos, modelSpacePosition - modelSpaceLightPos);

//added
vec4 texture2 = texture(colorTexture, colorCoord);

outputColor = ((ambientIntensity2 + (interpColor*2))/4) + 
((((interpColor) * lightIntensity2/200 * cosAngIncidence2) + (ambientIntensity2* interpColor )) 
/( ( sqrt(light2DistanceSqr) + light2DistanceSqr)/200 ));
//No outputColor for texture testing
outputColor =  texture2 ; 

}
}

这些都是着色器.以下是添加到.cpp的部分：

#include <glimg/glimg.h>
#include "../framework/directories.h"     
[...]
const int g_colorTexUnit = 0;
GLuint g_checkerTexture = 0;

这是纹理的加载器：

void LoadCheckerTexture()
{
try

{
std::string filename(LOCAL_FILE_DIR);
filename += "checker.dds";
std::auto_ptr<glimg::ImageSet>
 pImageSet(glimg::loaders::dds::LoadFromFile(filename.c_str()));

glGenTextures(1, &g_checkerTexture);
glBindTexture(GL_TEXTURE_2D, g_checkerTexture);

glimg::SingleImage image = pImageSet->GetImage(0, 0, 0);
glimg::Dimensions dims = image.GetDimensions();
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, dims.width, dims.height, 0, GL_BGRA, GL_UNSIGNED_INT_8_8_8_8_REV, image.GetImageData());

glBindTexture(GL_TEXTURE_2D, 0);
}
catch(std::exception &e)
{
printf("%s\n", e.what());
throw;
}
}

当然我在void init()中得到了这个：

LoadCheckerTexture();

然后在渲染对象时：

glActiveTexture(GL_TEXTURE0 + g_colorTexUnit);
glBindTexture(GL_TEXTURE_2D,g_checkerTexture);
g_pLeftMesh->Render();
glBindSampler(g_colorTexUnit, 0);
glBindTexture(GL_TEXTURE_2D, 0);

所有这一切,我把所有东西都变成黑色,但是当我将outputColor方程改为“texture outputColor;”时,一切看起来都很正常.我不知道我在这里做错了什么.一位朋友试图帮助我,我们删除了一些不必要的东西,但我们什么都没有运行.

解决方法:

好的,我已经完成了这一切,并设法以某种方式让它运行.首先,我必须添加采样器：

GLuint g_samplers;

//Add Later
void CreateSamplers()
{
glGenSamplers(1, &g_samplers);

    glSamplerParameteri(g_samplers, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glSamplerParameteri(g_samplers, GL_TEXTURE_WRAP_T, GL_REPEAT);

//Linear mipmap Nearest
glSamplerParameteri(g_samplers, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glSamplerParameteri(g_samplers, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
}

我还将此添加到文件中：

glimg::OpenGLPixelTransferParams xfer = glimg::GetUploadFormatType(pImageSet->GetFormat(), 0);

glimg::SingleImage image = pImageSet->GetImage(0, 0, 0);
glimg::Dimensions dims = image.GetDimensions();
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, dims.width, dims.height, 0, 
  xfer.format, xfer.type, image.GetImageData());

xfer变量确实将格式和类型调整为dds.
渲染代码也变成了这个：

//Added necessary 
glActiveTexture(GL_TEXTURE0 + g_colorTexUnit);
glBindTexture(GL_TEXTURE_2D,g_checkerTexture);
glBindSampler(g_colorTexUnit, g_samplers);
g_pLeftMesh->Render();
glBindSampler(g_colorTexUnit, 0);
glBindTexture(GL_TEXTURE_2D, 0);

当然在init()结束时我需要添加CreateSamplers的东西：

//Added this later
LoadCheckerTexture();
CreateSamplers();

对于所有这些问题我感到很遗憾,但是猜测OpenGL真的只是让人感到困惑,我只是运气不好.只是张贴这个让人们知道

标签：c,opengl,textures
来源： https://codeday.me/bug/20191003/1845808.html