OPENGL如何正確渲染具有不同紋理/映射的這兩個對象？
[英]OPENGL How do I correctly render these 2 objects with different textures/mapping?
問題描述
我試圖將普通映射和多維數據集映射合並到一個程序中，但是我很難使它們正確呈現。 在進行更復雜的工作之前，我正在做一個簡單的練習來幫助我完成這項工作。 我試圖將這兩個對象渲染到一個程序中。 它們都有不同的紋理，圓環使用立方體貼圖，而牆使用法線貼圖。
這些是它們本應分別顯示的樣子：
目前，這就是我所擁有的。 圓環可以正確渲染，但牆的紋理不會出現。
我為此使用了2個單獨的着色器程序，這是我第一次為一個程序使用多個着色器程序。 我懷疑我的問題可能與着色器變量的初始化有關，或者確實很明顯我沒有得到。 我正在為對象使用兩種不同的Vertex結構。
struct Vertex2
{
GLfloat position[3];
GLfloat normal[3];
GLfloat tangent[3];
GLfloat texCoord[2];
};
Vertex2 g_vertices[] = {
// Front: triangle 1
// vertex 1
-1.0f, 1.0f, 0.0f, // position
0.0f, 0.0f, 1.0f, // normal
1.0f, 0.0f, 0.0f, // tangent
0.0f, 1.0f, // texture coordinate
// vertex 2
-1.0f, -1.0f, 0.0f, // position
0.0f, 0.0f, 1.0f, // normal
1.0f, 0.0f, 0.0f, // tangent
0.0f, 0.0f, // texture coordinate
// vertex 3
1.0f, 1.0f, 0.0f, // position
0.0f, 0.0f, 1.0f, // normal
1.0f, 0.0f, 0.0f, // tangent
1.0f, 1.0f, // texture coordinate
// triangle 2
// vertex 1
1.0f, 1.0f, 0.0f, // position
0.0f, 0.0f, 1.0f, // normal
1.0f, 0.0f, 0.0f, // tangent
1.0f, 1.0f, // texture coordinate
// vertex 2
-1.0f, -1.0f, 0.0f, // position
0.0f, 0.0f, 1.0f, // normal
1.0f, 0.0f, 0.0f, // tangent
0.0f, 0.0f, // texture coordinate
// vertex 3
1.0f, -1.0f, 0.0f, // position
0.0f, 0.0f, 1.0f, // normal
1.0f, 0.0f, 0.0f, // tangent
1.0f, 0.0f, // texture coordinate
};
Main.cpp初始化函數：
static void init(GLFWwindow* window)
{
glEnable(GL_DEPTH_TEST); // enable depth buffer test
glEnable(GL_TEXTURE_2D);
// read the image data
GLint imageWidth[5]; //image width info
GLint imageHeight[5]; //image height info
g_texImage[FRONT] = readBitmapRGBImage("images/cm_front.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[BACK] = readBitmapRGBImage("images/cm_back.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[LEFT] = readBitmapRGBImage("images/cm_left.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[RIGHT] = readBitmapRGBImage("images/cm_right.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[TOP] = readBitmapRGBImage("images/cm_top.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[BOTTOM] = readBitmapRGBImage("images/cm_bottom.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[6] = readBitmapRGBImage("images/Fieldstone.bmp", &imageWidth[1], &imageHeight[1]);
g_texImage[7] = readBitmapRGBImage("images/FieldstoneBumpDOT3.bmp", &imageWidth[2], &imageHeight[2]);
glGenTextures(10, g_textureID);
// ...
// create and compile our GLSL program from the shader files
g_shaderProgramID[0] = loadShaders("CubeEnvMapVS.vert", "CubeEnvMapFS.frag");
g_shaderProgramID[1] = loadShaders("NormalMappingVS.vert", "NormalMappingFS.frag");
// find the location of shader variables
for (int i = 0; i < 2; i++)
{
positionIndex[i] = glGetAttribLocation(g_shaderProgramID[i], "aPosition");
normalIndex[i] = glGetAttribLocation(g_shaderProgramID[i], "aNormal");
texCoordIndex[i] = glGetAttribLocation(g_shaderProgramID[i], "aTexCoord");
g_MVP_Index[i] = glGetUniformLocation(g_shaderProgramID[i], "uModelViewProjectionMatrix");
g_M_Index[i] = glGetUniformLocation(g_shaderProgramID[i], "uModelMatrix");
g_viewPointIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uViewPoint");
g_lightPositionIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uLightingProperties.position");
g_lightAmbientIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uLightingProperties.ambient");
g_lightDiffuseIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uLightingProperties.diffuse");
g_lightSpecularIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uLightingProperties.specular");
g_lightShininessIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uLightingProperties.shininess");
g_materialAmbientIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uMaterialProperties.ambient");
g_materialDiffuseIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uMaterialProperties.diffuse");
g_materialSpecularIndex[i] = glGetUniformLocation(g_shaderProgramID[i], "uMaterialProperties.specular");
}
g_envMapSamplerIndex = glGetUniformLocation(g_shaderProgramID[0], "uEnvironmentMap");
tangentIndex = glGetAttribLocation(g_shaderProgramID[1], "aTangent");
g_texSamplerIndex = glGetUniformLocation(g_shaderProgramID[1], "uTextureSampler");
g_normalSamplerIndex = glGetUniformLocation(g_shaderProgramID[1], "uNormalSampler");
// initialise model matrix to the identity matrix
g_mm_torus = glm::mat4(1.0f);
g_mm_wall = mat4(1.0f);
// ...
// load mesh
// load_mesh("models/sphere.obj");
load_mesh("models/torus.obj");
// ...
// generate identifier for VBOs and copy data to GPU
glGenBuffers(5, g_VBO);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex)*g_numberOfVertices, g_pMeshVertices, GL_STATIC_DRAW);
// generate identifier for IBO and copy data to GPU
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_VBO[1]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLint) * 3 * g_numberOfFaces, g_pMeshIndices, GL_STATIC_DRAW);
// generate identifiers for VAO
glGenVertexArrays(5, g_VAO);
// create VAO and specify VBO data
glBindVertexArray(g_VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[0]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_VBO[1]);
glVertexAttribPointer(positionIndex[0], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, position)));
glVertexAttribPointer(normalIndex[0], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, normal)));
glEnableVertexAttribArray(positionIndex[0]); // enable vertex attributes
glEnableVertexAttribArray(normalIndex[0]);
// generate identifier for VBOs and copy data to GPU
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[2]);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertices), g_vertices, GL_STATIC_DRAW);
// create VAO and specify VBO data
glBindVertexArray(g_VAO[1]);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[2]);
glVertexAttribPointer(positionIndex[1], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex2), reinterpret_cast<void*>(offsetof(Vertex2, position)));
glVertexAttribPointer(normalIndex[1], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex2), reinterpret_cast<void*>(offsetof(Vertex2, normal)));
glVertexAttribPointer(tangentIndex, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex2), reinterpret_cast<void*>(offsetof(Vertex2, tangent)));
glVertexAttribPointer(texCoordIndex[0], 2, GL_FLOAT, GL_FALSE, sizeof(Vertex2), reinterpret_cast<void*>(offsetof(Vertex2, texCoord)));
// enable vertex attributes
glEnableVertexAttribArray(positionIndex[1]);
glEnableVertexAttribArray(normalIndex[1]);
glEnableVertexAttribArray(tangentIndex);
glEnableVertexAttribArray(texCoordIndex[0]);
}
渲染場景功能：
static void render_scene()
{
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // clear colour buffer and depth buffer
glUseProgram(g_shaderProgramID[0]); // use the shaders associated with the shader program
glBindVertexArray(g_VAO[0]); // make VAO active
// set uniform shader variables
glm::mat4 MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_torus;
glUniformMatrix4fv(g_MVP_Index[0], 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index[0], 1, GL_FALSE, &g_mm_torus[0][0]);
glUniform3fv(g_viewPointIndex[0], 1, &g_camera.getPosition()[0]);
glUniform4fv(g_lightPositionIndex[0], 1, &g_lightProperties.position[0]);
glUniform4fv(g_lightAmbientIndex[0], 1, &g_lightProperties.ambient[0]);
glUniform4fv(g_lightDiffuseIndex[0], 1, &g_lightProperties.diffuse[0]);
glUniform4fv(g_lightSpecularIndex[0], 1, &g_lightProperties.specular[0]);
glUniform1fv(g_lightShininessIndex[0], 1, &g_lightProperties.shininess);
glUniform4fv(g_materialAmbientIndex[0], 1, &g_materialProperties.ambient[0]);
glUniform4fv(g_materialDiffuseIndex[0], 1, &g_materialProperties.diffuse[0]);
glUniform4fv(g_materialSpecularIndex[0], 1, &g_materialProperties.specular[0]);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_CUBE_MAP, g_textureID[0]);
glUniform1i(g_envMapSamplerIndex, 0);
glDrawElements(GL_TRIANGLES, g_numberOfFaces * 3, GL_UNSIGNED_INT, 0); // display the vertices based on their indices and primitive type
glUseProgram(g_shaderProgramID[1]); // use the shaders associated with the shader program
glBindVertexArray(g_VAO[1]); // make VAO active
// set uniform shader variables
glClear(GL_DEPTH_BUFFER_BIT);
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_wall;
glUniformMatrix4fv(g_MVP_Index[1], 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index[1], 1, GL_FALSE, &g_mm_wall[0][0]);
glUniform3fv(g_viewPointIndex[1], 1, &g_camera.getPosition()[0]);
glUniform4fv(g_lightPositionIndex[1], 1, &g_lightProperties.position[0]);
glUniform4fv(g_lightAmbientIndex[1], 1, &g_lightProperties.ambient[0]);
glUniform4fv(g_lightDiffuseIndex[1], 1, &g_lightProperties.diffuse[0]);
glUniform4fv(g_lightSpecularIndex[1], 1, &g_lightProperties.specular[0]);
glUniform1fv(g_lightShininessIndex[1], 1, &g_lightProperties.shininess);
glUniform4fv(g_materialAmbientIndex[1], 1, &g_materialProperties.ambient[0]);
glUniform4fv(g_materialDiffuseIndex[1], 1, &g_materialProperties.diffuse[0]);
glUniform4fv(g_materialSpecularIndex[1], 1, &g_materialProperties.specular[0]);
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, g_textureID[6]);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, g_textureID[7]);
glUniform1i(g_texSamplerIndex, 1);
glUniform1i(g_normalSamplerIndex, 2);
glDrawArrays(GL_TRIANGLES, 0, 36);
glFlush(); // flush the pipeline
}
環形着色器的頂點着色器：
#version 330 core
// input data (different for all executions of this shader)
in vec3 aPosition;
in vec3 aNormal;
// uniform input data
uniform mat4 uModelViewProjectionMatrix;
uniform mat4 uModelMatrix;
// output data (will be interpolated for each fragment)
out vec3 vNormal;
out vec3 vPosition;
void main()
{
// set vertex position
gl_Position = uModelViewProjectionMatrix * vec4(aPosition, 1.0);
// world space
vPosition = (uModelMatrix * vec4(aPosition, 1.0)).xyz;
vNormal = (uModelMatrix * vec4(aNormal, 0.0)).xyz;
}
圓環的片段着色器：
#version 330 core
// interpolated values from the vertex shaders
in vec3 vNormal;
in vec3 vPosition;
// uniform input data
struct LightProperties
{
vec4 position;
vec4 ambient;
vec4 diffuse;
vec4 specular;
float shininess;
};
struct MaterialProperties
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
};
uniform LightProperties uLightingProperties;
uniform MaterialProperties uMaterialProperties;
uniform vec3 uViewPoint;
uniform samplerCube uEnvironmentMap;
// output data
out vec3 fColor;
void main()
{
vec3 N = normalize(vNormal);
vec3 L;
// determine whether the light is a point light source or directional light
if(uLightingProperties.position.w == 0.0f)
L = normalize((uLightingProperties.position).xyz);
else
L = normalize((uLightingProperties.position).xyz - vPosition);
vec3 V = normalize(uViewPoint - vPosition);
vec3 R = reflect(-L, N);
// calculate the ambient, diffuse and specular components
vec4 ambient = uLightingProperties.ambient * uMaterialProperties.ambient;
vec4 diffuse = uLightingProperties.diffuse * uMaterialProperties.diffuse * max(dot(L, N), 0.0);
vec4 specular = vec4(0.0f, 0.0f, 0.0f, 1.0f);
if(dot(L, N) > 0.0f)
{
specular = uLightingProperties.specular * uMaterialProperties.specular
* pow(max(dot(V, R), 0.0), uLightingProperties.shininess);
}
vec3 reflectEnvMap = reflect(-V, N);
// set output color
fColor = texture(uEnvironmentMap, reflectEnvMap).rgb;
fColor *= (diffuse + specular + ambient).rgb;
}
牆的頂點着色器：
#version 330 core
// input data (different for all executions of this shader)
in vec3 aPosition;
in vec3 aNormal;
in vec3 aTangent;
in vec2 aTexCoord;
// uniform input data
uniform mat4 uModelViewProjectionMatrix;
uniform mat4 uModelMatrix;
// output data (will be interpolated for each fragment)
out vec3 vPosition;
out vec3 vNormal;
out vec3 vTangent;
out vec2 vTexCoord;
void main()
{
// set vertex position
gl_Position = uModelViewProjectionMatrix * vec4(aPosition, 1.0);
// world space
vPosition = (uModelMatrix * vec4(aPosition, 1.0)).xyz;
vNormal = (uModelMatrix * vec4(aNormal, 0.0)).xyz;
vTangent = (uModelMatrix * vec4(aTangent, 0.0)).xyz;
vTexCoord = aTexCoord;
}
牆的片段着色器：
#version 330 core
// interpolated values from the vertex shaders
in vec3 vPosition;
in vec3 vNormal;
in vec3 vTangent;
in vec2 vTexCoord;
// uniform input data
struct LightProperties
{
vec4 position;
vec4 ambient;
vec4 diffuse;
vec4 specular;
float shininess;
};
struct MaterialProperties
{
vec4 ambient;
vec4 diffuse;
vec4 specular;
};
uniform LightProperties uLightingProperties;
uniform MaterialProperties uMaterialProperties;
uniform vec3 uViewPoint;
uniform sampler2D uTextureSampler;
uniform sampler2D uNormalSampler;
// output data
out vec3 fColor;
void main()
{
// calculate normal map vectors
vec3 normal = normalize(vNormal);
vec3 tangent = normalize(vTangent);
vec3 biTangent = normalize(cross(tangent, normal));
vec3 normalMap = 2.0f * texture(uNormalSampler, vTexCoord).xyz - 1.0f;
// calculate vectors for lighting
vec3 N = normalize(mat3(tangent, biTangent, normal) * normalMap);
vec3 L;
// determine whether the light is a point light source or directional light
if(uLightingProperties.position.w == 0.0f)
L = normalize((uLightingProperties.position).xyz);
else
L = normalize((uLightingProperties.position).xyz - vPosition);
vec3 V = normalize(uViewPoint - vPosition);
vec3 R = reflect(-L, N);
// calculate Phong lighting
vec4 ambient = uLightingProperties.ambient * uMaterialProperties.ambient;
vec4 diffuse = uLightingProperties.diffuse * uMaterialProperties.diffuse * max(dot(L, N), 0.0);
vec4 specular = vec4(0.0f, 0.0f, 0.0f, 1.0f);
if(dot(L, N) > 0.0f)
{
specular = uLightingProperties.specular * uMaterialProperties.specular
* pow(max(dot(V, R), 0.0), uLightingProperties.shininess);
}
// set output color
fColor = (diffuse + specular + ambient).rgb;
fColor *= texture(uTextureSampler, vTexCoord).rgb;
}
PS：對不起，如果我昨天對我的問題有點不負責任。 我只是不明白，因此沒有回音的一些建議。
1 個解決方案
解決方案1
1 已采納 2017-08-20 17:09:29
繪制第二部分（牆）時，將紋理綁定到紋理單元GL_TEXTURE1和GL_TEXTURE2 ：
glActiveTexture(GL_TEXTURE1);
glBindTexture(GL_TEXTURE_2D, g_textureID[6]);
glActiveTexture(GL_TEXTURE2);
glBindTexture(GL_TEXTURE_2D, g_textureID[7]);
但是，您正在將紋理單元索引0和1設置為紋理采樣器制服uTextureSampler和uNormalSampler ：
glUniform1i(g_texSamplerIndex, 0);
glUniform1i(g_normalSamplerIndex, 1);`
像這樣修改您的代碼：
glUniform1i(g_texSamplerIndex, 1); // GL_TEXTURE1
glUniform1i(g_normalSamplerIndex, 2); // GL_TEXTURE2
此外，將"aTexCoord"的屬性索引存儲到g_shaderProgramID[i] texCoordIndex[i]中：
for (int i = 0; i < 2; i++)
{
....
texCoordIndex[i] = glGetAttribLocation(g_shaderProgramID[i], "aTexCoord");
.....
}
在設置頂點屬性指針並啟用頂點屬性時，您必須意識到這一點。
更改此：
glVertexAttribPointer(texCoordIndex[0], 2, GL_FLOAT, GL_FALSE, sizeof(Vertex2), reinterpret_cast<void*>(offsetof(Vertex2, texCoord)));
.....
glEnableVertexAttribArray(texCoordIndex[0]);
對此：
glVertexAttribPointer(texCoordIndex[1], 2, GL_FLOAT, GL_FALSE, sizeof(Vertex2), reinterpret_cast<void*>(offsetof(Vertex2, texCoord)));
.....
glEnableVertexAttribArray(texCoordIndex[1]);
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