问题
I am trying to make a glass plane by adjusting the translucency of the object with alpha values. Currently, it is a black plane as my alpha values have no effect on my objects. Please have a look at the image:
glEnable(GL_BLEND); does nothing
and
glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ZERO); makes all my objects disappear
fragment shader:
#version 330 core
// interpolated values from the vertex shaders
in vec3 vNormal;
in vec3 vPosition;
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 input data
uniform float uAlpha;
// output data
out vec4 fColor;
void main()
{
// calculate vectors for lighting
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);
vec3 colour = vec3(0.0f, 0.0f, 0.0f);
// 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
colour = (diffuse + specular + ambient).rgb;
colour *= texture(uTextureSampler, vTexCoord).rgb;
fColor = vec4(colour, uAlpha);
//fColor = texture(uTextureSampler, vTexCoord).rgb;
}
This gives me an opaque black plane when what I want is a translucent black plane.
static void init(GLFWwindow* window)
{
glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
glEnable(GL_DEPTH_TEST);
glEnable(GL_BLEND);
//glBlendEquationSeparate(GL_FUNC_ADD, GL_FUNC_ADD);
//glBlendFuncSeparate(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA, GL_ONE, GL_ZERO);
// read image data
g_texImage[0] = readBitmapRGBImage("images/check.bmp", &imageWidth[0], &imageHeight[0]);
g_texImage[1] = readBitmapRGBImage("images/smile.bmp", &imageWidth[1], &imageHeight[1]);
g_texImage[2] = readBitmapRGBImage("images/Fieldstone.bmp", &imageWidth[2], &imageHeight[2]);
g_texImage[3] = readBitmapRGBImage("images/sunflower.bmp", &imageWidth[3], &imageHeight[3]);
g_texImage[4] = readBitmapRGBImage("images/painting.bmp", &imageWidth[4], &imageHeight[4]);
// create and compile GLSL program from the shader files
g_shaderProgramID[0] = loadShaders("vertex_shaderL.vert", "fragment_shaderL.frag");
g_shaderProgramID[1] = loadShaders("vertex_shaderT.vert", "fragment_shaderT.frag");
// find the locations of shader variables
GLuint positionIndex[2];
positionIndex[0] = glGetAttribLocation(g_shaderProgramID[0], "aPosition");
GLuint normalIndex = glGetAttribLocation(g_shaderProgramID[0], "aNormal");
GLuint texCoordIndex = glGetAttribLocation(g_shaderProgramID[0], "aTexCoord");
g_MVP_Index = glGetUniformLocation(g_shaderProgramID[0], "uModelViewProjectionMatrix");
g_M_Index = glGetUniformLocation(g_shaderProgramID[0], "uModelMatrix");
g_viewPointIndex = glGetUniformLocation(g_shaderProgramID[0], "uViewPoint");
g_alphaIndex = glGetUniformLocation(g_shaderProgramID[0], "uAlpha");
g_texSampler_Index[0] = glGetUniformLocation(g_shaderProgramID[0], "uTextureSampler");
g_lightPositionIndex = glGetUniformLocation(g_shaderProgramID[0], "uLightingProperties.position");
g_lightAmbientIndex = glGetUniformLocation(g_shaderProgramID[0], "uLightingProperties.ambient");
g_lightDiffuseIndex = glGetUniformLocation(g_shaderProgramID[0], "uLightingProperties.diffuse");
g_lightSpecularIndex = glGetUniformLocation(g_shaderProgramID[0], "uLightingProperties.specular");
g_lightShininessIndex = glGetUniformLocation(g_shaderProgramID[0], "uLightingProperties.shininess");
g_materialAmbientIndex = glGetUniformLocation(g_shaderProgramID[0], "uMaterialProperties.ambient");
g_materialDiffuseIndex = glGetUniformLocation(g_shaderProgramID[0], "uMaterialProperties.diffuse");
g_materialSpecularIndex = glGetUniformLocation(g_shaderProgramID[0], "uMaterialProperties.specular");
positionIndex[1] = glGetAttribLocation(g_shaderProgramID[1], "aPosition");
g_texSampler_Index[1] = glGetUniformLocation(g_shaderProgramID[1], "uTextureSampler");
g_renderDepth_Index = glGetUniformLocation(g_shaderProgramID[1], "uRenderDepth");
// initialise model matrices
g_mm_floor = translate(vec3(0.2f, -4.0f, 0.0f));
g_mm_cube = translate(vec3(0.0f, -4.0f, 0.0f)) * scale(vec3(2.0f, 2.0f, 2.0f));
for (int i = 0; i < 4; i++)
{
g_mm_wall[i] = mat4(1.0f);
}
g_mm_painting[0] = mat4(1.0f);
g_mm_painting[1] = mat4(1.0f);
g_mm_glass = mat4(1.0f);
g_mm_torus = mat4(1.0f);
int width, height;
glfwGetFramebufferSize(window, &width, &height);
float aspectRatio = static_cast<float>(width) / height;
// camera
g_camera.setViewMatrix(vec3(0, 1, 10), vec3(0, 0, -10), vec3(0, 1, 0));
g_camera.setProjectionMatrix(perspective(45.0f, aspectRatio, 0.1f, 100.0f));
// initialise light and material properties
g_lightProperties.position = vec4(7.0f, 5.0f, 0.0f, 1.0f);
g_lightProperties.ambient = vec4(1.0f, 1.0f, 1.0f, 1.0f);
g_lightProperties.diffuse = vec4(1.0f, 1.0f, 1.0f, 1.0f);
g_lightProperties.specular = vec4(1.0f, 1.0f, 1.0f, 1.0f);
g_lightProperties.shininess = 10.0f;
g_materialProperties[0].ambient = vec4(0.3f, 0.3f, 0.3f, 1.0f);
g_materialProperties[0].diffuse = vec4(0.8f, 0.8f, 0.4f, 1.0f);
g_materialProperties[0].specular = vec4(0.8f, 0.8f, 0.4f, 1.0f);
g_materialProperties[1].ambient = vec4(0.3f, 0.3f, 0.3f, 1.0f);
g_materialProperties[1].diffuse = vec4(0.2f, 0.7f, 1.0f, 1.0f);
g_materialProperties[1].specular = vec4(0.2f, 0.7f, 1.0f, 1.0f);
g_materialProperties[2].ambient = vec4(0.3f, 0.3f, 0.3f, 1.0f);
g_materialProperties[2].diffuse = vec4(0.2f, 0.7f, 0.2f, 1.0f);
g_materialProperties[2].specular = vec4(0.2f, 0.7f, 0.2f, 1.0f);
// generate identifier for texture object and set texture properties
// checkered floor
glGenTextures(10, g_textureID);
glBindTexture(GL_TEXTURE_2D, g_textureID[0]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, imageWidth[0], imageHeight[0], 0, GL_BGR, GL_UNSIGNED_BYTE, g_texImage[0]);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// smiley face
glBindTexture(GL_TEXTURE_2D, g_textureID[1]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, imageWidth[1], imageHeight[1], 0, GL_BGR, GL_UNSIGNED_BYTE, g_texImage[1]);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// fieldstone wallpaper
glBindTexture(GL_TEXTURE_2D, g_textureID[2]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, imageWidth[2], imageHeight[2], 0, GL_BGR, GL_UNSIGNED_BYTE, g_texImage[2]);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// sunflower painting
glBindTexture(GL_TEXTURE_2D, g_textureID[3]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, imageWidth[3], imageHeight[3], 0, GL_BGR, GL_UNSIGNED_BYTE, g_texImage[3]);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// other painting
glBindTexture(GL_TEXTURE_2D, g_textureID[4]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, imageWidth[4], imageHeight[4], 0, GL_BGR, GL_UNSIGNED_BYTE, g_texImage[4]);
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
// textures to be rendered to (i.e. render-to-texture)
glBindTexture(GL_TEXTURE_2D, g_textureID[6]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, g_windowWidth, g_windowHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glBindTexture(GL_TEXTURE_2D, g_textureID[7]);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT16, g_windowWidth, g_windowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// set up framebuffer object
glGenFramebuffers(1, &g_FBO);
glBindFramebuffer(GL_FRAMEBUFFER, g_FBO);
GLuint depthRenderBufferID;
glGenRenderbuffers(1, &depthRenderBufferID);
glBindRenderbuffer(GL_RENDERBUFFER, depthRenderBufferID);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT, g_windowWidth, g_windowHeight);
glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthRenderBufferID);
// associate respective textures with framebuffer attachments
glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, g_textureID[6], 0);
glFramebufferTexture(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, g_textureID[7], 0);
// number of draw buffers
GLenum drawBuffers[1] = { GL_COLOR_ATTACHMENT0 };
glDrawBuffers(1, drawBuffers);
if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
exit(EXIT_FAILURE);
// generate identifier for VBOs and copy data to GPU
glGenBuffers(10, g_VBO);
glGenVertexArrays(10, g_VAO);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[0]);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_vertices), g_vertices, GL_STATIC_DRAW);
glBindVertexArray(g_VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[0]);
glVertexAttribPointer(positionIndex[0], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, position)));
glVertexAttribPointer(normalIndex, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, normal)));
glVertexAttribPointer(texCoordIndex, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, texCoord)));
glEnableVertexAttribArray(positionIndex[0]);
glEnableVertexAttribArray(normalIndex);
glEnableVertexAttribArray(texCoordIndex);
// to display the render-to-texture's texture on a screen space quad
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[1]);
glBufferData(GL_ARRAY_BUFFER, sizeof(g_screenspaceQuad), g_screenspaceQuad, GL_STATIC_DRAW);
glBindVertexArray(g_VAO[1]);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[1]);
glVertexAttribPointer(positionIndex[1], 3, GL_FLOAT, GL_FALSE, 0, 0);
glEnableVertexAttribArray(positionIndex[1]);
// torus mesh
load_mesh("models/torus.obj", 0);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[2]);
glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex)*g_numberOfVertices[0], g_pMeshVertices[0], GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_VBO[3]);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(GLint) * 3 * g_numberOfFaces[0], g_pMeshIndices[0], GL_STATIC_DRAW);
glBindVertexArray(g_VAO[2]);
glBindBuffer(GL_ARRAY_BUFFER, g_VBO[2]);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_VBO[3]);
glVertexAttribPointer(positionIndex[0], 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, position)));
glVertexAttribPointer(normalIndex, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), reinterpret_cast<void*>(offsetof(Vertex, normal)));
glEnableVertexAttribArray(positionIndex[0]);
glEnableVertexAttribArray(normalIndex);
}
static void render_scene()
{
// draw to frame buffer object
glBindFramebuffer(GL_FRAMEBUFFER, g_FBO);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(g_shaderProgramID[0]);
glBindVertexArray(g_VAO[0]);
// set lighting properties
glUniform4fv(g_lightPositionIndex, 1, &g_lightProperties.position[0]);
glUniform4fv(g_lightAmbientIndex, 1, &g_lightProperties.ambient[0]);
glUniform4fv(g_lightDiffuseIndex, 1, &g_lightProperties.diffuse[0]);
glUniform4fv(g_lightSpecularIndex, 1, &g_lightProperties.specular[0]);
glUniform1fv(g_lightShininessIndex, 1, &g_lightProperties.shininess);
// set uniform shader variables
mat4 MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_glass;
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_glass[0][0]);
glUniform1f(g_alphaIndex, 0.5);
// set material properties
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[0].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[0].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[0].specular[0]);
// draw glass
glDrawArrays(GL_TRIANGLES, 0, 6);
// set uniform shader variables
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_cube;
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_cube[0][0]);
glUniform1f(g_alphaIndex, 1.0);
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[2].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[2].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[2].specular[0]);
// draw cube
glBindTexture(GL_TEXTURE_2D, g_textureID[1]);
glDrawArrays(GL_TRIANGLES, 6, 36);
// set uniform shader variables
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_floor;
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_floor[0][0]);
glUniform1f(g_alphaIndex, 1.0);
// set material properties
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[0].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[0].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[0].specular[0]);
// draw floor
glBindTexture(GL_TEXTURE_2D, g_textureID[0]);
glDrawArrays(GL_TRIANGLES, 0, 6);
for (int i = 0; i < 3; i++)
{
// set uniform shader variables
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_wall[i];
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_wall[i][0][0]);
glUniform1f(g_alphaIndex, 1.0);
// set material properties
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[1].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[1].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[1].specular[0]);
// draw walls
glBindTexture(GL_TEXTURE_2D, g_textureID[2]);
glDrawArrays(GL_TRIANGLES, 0, 6);
}
// set uniform shader variables
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_painting[0];
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_painting[0][0][0]);
glUniform1f(g_alphaIndex, 1.0);
// set material properties
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[2].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[2].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[2].specular[0]);
// draw apples painting
glBindTexture(GL_TEXTURE_2D, g_textureID[3]);
glDrawArrays(GL_TRIANGLES, 0, 6);
// set uniform shader variables
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_painting[1];
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_painting[1][0][0]);
glUniform1f(g_alphaIndex, 1.0);
// set material properties
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[2].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[2].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[2].specular[0]);
// draw other painting
if (newpainting == false)
glBindTexture(GL_TEXTURE_2D, g_textureID[4]);
else
glBindTexture(GL_TEXTURE_2D, g_textureID[5]);
glDrawArrays(GL_TRIANGLES, 0, 6);
// set uniform shader variables
glBindVertexArray(g_VAO[2]);
MVP = g_camera.getProjectionMatrix() * g_camera.getViewMatrix() * g_mm_torus;
glUniformMatrix4fv(g_MVP_Index, 1, GL_FALSE, &MVP[0][0]);
glUniformMatrix4fv(g_M_Index, 1, GL_FALSE, &g_mm_torus[0][0]);
glUniform1f(g_alphaIndex, 1.0);
// set material properties
glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties[0].ambient[0]);
glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties[0].diffuse[0]);
glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties[0].specular[0]);
// draw torus
glDrawElements(GL_TRIANGLES, g_numberOfFaces[0] * 3, GL_UNSIGNED_INT, 0);
// draw to normal display
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glUseProgram(g_shaderProgramID[1]);
glBindVertexArray(g_VAO[1]);
glUniform1i(g_texSampler_Index[1], 0);
// draw screenspace quad
glActiveTexture(GL_TEXTURE0);
if (g_bRenderDepth)
{
glUniform1i(g_renderDepth_Index, 1);
glBindTexture(GL_TEXTURE_2D, g_textureID[7]);
}
else
{
glUniform1i(g_renderDepth_Index, 0);
glBindTexture(GL_TEXTURE_2D, g_textureID[6]);
}
glDrawArrays(GL_TRIANGLES, 0, 6);
glFlush();
}
回答1:
When rendering transparent objects, it is important to render everything in the correct order. That is:
- Render all opaque objects
- Render all transparent objects (if there are multiple, then you'll have to sort them back to front.
Currently, you are rendering the glass object first, which sets the depth values in the depth buffer. All objects behind the glass will never be draw because they fail the z-test.
来源：https://stackoverflow.com/questions/45770076/rendering-transparent-objects