我有一个场景，其中包含多个GLSL程序（OpenGL 3.3）。这些程序使用不同的着色器，这些着色器是相似的，但是（将）有所不同。而且我有一个统一的ivec4 char1，所有版本的名称都相同，这对所有程序都具有相同的含义和价值。着色器中的dot1(...)函数中使用了此制服。着色器中的main()函数中使用了此制服。
fragment3d.glsl：
#version 330 core
smooth in vec4 vertexPosition;
smooth in vec4 vertexColor;
smooth in vec4 vertexNormal;
out vec4 fragmentColor;
uniform ivec4 char1;
uniform float shineness;
float dot1(vec4 x, vec4 y)
{
float result = 0.0;
for (int i = 0; i < 4; i++)
{
result += char1[i] * x[i] * y[i];
}
return result;
}
void main()
{
if (vertexNormal == vec4(0.0, 0.0, 0.0, 0.0))
{
fragmentColor = vertexColor;
}
else
{
vec4 lightDirection = vec4(1.0, 0.0, 0.0, 0.0) - vertexPosition;
float lightNormInverse = inversesqrt(dot1(lightDirection, lightDirection));
lightDirection *= lightNormInverse;
float diffuseCoefficient = dot1(lightDirection, vertexNormal);
vec4 reflectedDirection = 2 * diffuseCoefficient * vertexNormal - lightDirection;
diffuseCoefficient = abs(diffuseCoefficient);
float specularCoefficient = max(dot1(reflectedDirection, lightDirection), 0.0);
if (specularCoefficient > 0.0 && shineness > 0.0)
{
specularCoefficient = pow(specularCoefficient, shineness);
}
vec3 diffuseColor = clamp(vertexColor.rgb * diffuseCoefficient, 0.0, 1.0);
vec3 specularColor = clamp(vec3(0.5, 0.5, 0.5) * specularCoefficient, 0.0, 1.0);
fragmentColor.rgb = diffuseColor + specularColor;
fragmentColor.a = 1.0 - diffuseCoefficient * (1.0 - vertexColor.a);
}
}
fragment3d-new.glsl
#version 330 core
smooth in vec4 geometryPosition;
smooth in vec4 geometryNormal;
smooth in vec4 geometryColor;
out vec4 fragmentColor;
uniform ivec4 char1;
uniform float shineness;
float dot1(vec4 x, vec4 y)
{
float result = 0.0;
for (int i = 0; i < 4; i++)
{
result += char1[i] * x[i] * y[i];
}
return result;
}
void main()
{
if (geometryNormal == vec4(0.0, 0.0, 0.0, 0.0))
{
fragmentColor = geometryColor;
}
else
{
vec4 lightDirection = vec4(1.0, 0.0, 0.0, 0.0) - geometryPosition;
float lightNormInverse = inversesqrt(dot1(lightDirection, lightDirection));
lightDirection *= lightNormInverse;
float diffuseCoefficient = dot1(lightDirection, geometryNormal);
vec4 reflectedDirection = 2 * diffuseCoefficient * geometryNormal - lightDirection;
diffuseCoefficient = abs(diffuseCoefficient);
float specularCoefficient = max(dot1(reflectedDirection, lightDirection), 0.0);
if (specularCoefficient > 0.0 && shineness > 0.0)
{
specularCoefficient = pow(specularCoefficient, shineness);
}
vec3 diffuseColor = clamp(geometryColor.rgb * diffuseCoefficient, 0.0, 1.0);
vec3 specularColor = clamp(vec3(0.5, 0.5, 0.5) * specularCoefficient, 0.0, 1.0);
fragmentColor.rgb = diffuseColor + specularColor;
fragmentColor.a = 1.0 - diffuseCoefficient * (1.0 - geometryColor.a);
}
}
初始化C ++代码为：
glUseProgram(0);
if (m_glProgram[GEOMETRY] != 0)
{
glDeleteProgram(m_glProgram[GEOMETRY]);
}
if (m_glProgram[TRIANGLE] != 0)
{
glDeleteProgram(m_glProgram[TRIANGLE]);
}
if (m_glProgram[TEXTURE] != 0)
{
glDeleteProgram(m_glProgram[TEXTURE]);
}
GLuint vertexShaderGeometry = compileShader(GL_VERTEX_SHADER, vertex, ss);
GLuint fragmentShaderGeometry = compileShader(GL_FRAGMENT_SHADER, fragment, ss);
vector<GLuint> shadersGeometry = {vertexShaderGeometry, fragmentShaderGeometry};
m_glProgram[GEOMETRY] = compileProgram(shadersGeometry, ss);
glUseProgram(m_glProgram[GEOMETRY]);
m_glUniform[GEOMETRY_PROJECTION] = glGetUniformLocation(m_glProgram[GEOMETRY], "projection"); // Set in changeProjection(...)
m_glUniform[GEOMETRY_ORIENTATION] = glGetUniformLocation(m_glProgram[GEOMETRY], "orientation"); // Set in changeOrientation(...)
m_glUniform[GEOMETRY_MODE] = glGetUniformLocation(m_glProgram[GEOMETRY], "mode"); // Set here
m_glUniform[GEOMETRY_CHAR1] = glGetUniformLocation(m_glProgram[GEOMETRY], "char1"); // Set here
m_glUniform[GEOMETRY_SHANENESS] = glGetUniformLocation(m_glProgram[GEOMETRY], "shineness"); // Set here? For now it is hardcoded.
cleanProgram(m_glProgram[GEOMETRY], shadersGeometry);
if (m_glUniform[GEOMETRY_MODE] >= 0 && dim == 2)
{
// TODO Add configuration for Poincare model.
// For now, Beltrami-Klein is hardcoded.
glUniform1i(m_glUniform[GEOMETRY_MODE], 1);
}
if (m_glUniform[GEOMETRY_CHAR1] >= 0)
{
GLint char1[4];
char1[0] = m_projected.chars(0);
char1[1] = 1;
char1[2] = m_projected.chars(1);
char1[3] = m_projected.chars(1, 2);
glUniform4iv(m_glUniform[GEOMETRY_CHAR1], 1, char1);
}
if (m_glUniform[GEOMETRY_SHANENESS] >= 0)
{
// Add it to configuration. For now it is hardcoded.
glUniform1f(m_glUniform[GEOMETRY_SHANENESS], 1.0);
}
////////////////////////////////////////////////////////
if (dim == 3)
{
GLuint vertexShaderNew3d = compileShader(GL_VERTEX_SHADER, "vertex3d-new.glsl", ss);
GLuint geometryShaderNew3d = compileShader(GL_GEOMETRY_SHADER, "geometry3d-new.glsl", ss);
GLuint fragmentShaderNew3d = compileShader(GL_FRAGMENT_SHADER, "fragment3d-new.glsl", ss);
m_glProgram[TRIANGLE] = compileProgram({vertexShaderNew3d, geometryShaderNew3d, fragmentShaderNew3d}, ss);
glUseProgram(TRIANGLE);
m_glUniform[PLANE_3D_PROJECTION] = glGetUniformLocation(m_glProgram[TRIANGLE], "projection"); // Set in changeProjection(...)
m_glUniform[PLANE_3D_ORIENTATION] = glGetUniformLocation(m_glProgram[TRIANGLE], "orientation"); // Set in changeOrientation(...)
m_glUniform[PLANE_3D_CHAR1] = glGetUniformLocation(m_glProgram[TRIANGLE], "char1"); // Set here
m_glUniform[PLANE_3D_SHANENESS] = glGetUniformLocation(m_glProgram[TRIANGLE], "shineness"); // Set here? For now it is hardcoded.
cout << "m_glProgram[PLANE_3D] = " << m_glProgram[TRIANGLE] << endl;
cout << "m_glUniform[PLANE_3D_PROJECTION] = " << m_glUniform[PLANE_3D_PROJECTION] << endl;
cout << "m_glUniform[PLANE_3D_ORIENTATION] = " << m_glUniform[PLANE_3D_ORIENTATION] << endl;
cout << "m_glUniform[PLANE_3D_CHAR1] = " << m_glUniform[PLANE_3D_CHAR1] << endl;
cout << "m_glUniform[PLANE_3D_SHANENESS] = " << m_glUniform[PLANE_3D_SHANENESS] << endl;
if (m_glUniform[PLANE_3D_CHAR1] >= 0)
{
GLint char1[4];
char1[0] = m_projected.chars(0);
char1[1] = 1;
char1[2] = m_projected.chars(1);
char1[3] = m_projected.chars(1, 2);
cout << "Before setting: "; for (int i = 0; i < 4; i++) {cout << char1[i] << ' ';} cout << endl;
glUniform4iv(m_glUniform[PLANE_3D_CHAR1], 1, char1);
glGetUniformiv(m_glProgram[TRIANGLE], m_glUniform[PLANE_3D_CHAR1], char1);
cout << "Read after setting: "; for (int i = 0; i < 4; i++) {cout << char1[i] << ' ';} cout << endl;
glGetUniformiv(m_glProgram[GEOMETRY], m_glUniform[GEOMETRY_CHAR1], char1);
cout << "Similar for GEOMETRY: "; for (int i = 0; i < 4; i++) {cout << char1[i] << ' ';} cout << endl;
}
if (m_glUniform[PLANE_3D_SHANENESS] >= 0)
{
// Add it to configuration. For now it is hardcoded.
glUniform1f(m_glUniform[PLANE_3D_SHANENESS], 1.0);
}
}
由于某种原因，ivec4 char1统一设置正确，可以使用m_glProgram[GEOMETRY]和统一m_glUniform[GEOMETRY_CHAR1]从第一个着色器读取，但是不能正确地使用{在第二个着色器中设置{1}}和统一的m_glProgram[TRIANGLE]。此代码的输出是：
m_glUniform[PLANE_3D_CHAR1]这意味着准备好的向量m_glProgram[PLANE_3D] = 5
m_glUniform[PLANE_3D_PROJECTION] = 1262
m_glUniform[PLANE_3D_ORIENTATION] = 1261
m_glUniform[PLANE_3D_CHAR1] = 1263
m_glUniform[PLANE_3D_SHANENESS] = 1264
Before setting: 0 1 1 1
Read after setting: 0 0 0 0
Similar for GEOMETRY: 0 1 1 1
在第一个着色器/程序中正确设置，而不在第二个着色器/程序中正确设置。查询其值将返回默认值[0, 1, 1, 1]。怎么了？
答案 0 :(得分：0)
如果通过glUniform4iv设置统一变量，则必须将着色器程序安装为当前渲染状态的一部分，因为glUniform4iv将值设置为当前着色器程序对象的默认统一块。参见glUseProgram。
TRIANGLE是存储在容器m_glProgram中的着色器程序对象的索引，但不是着色器程序对象本身的索引。
这意味着glUseProgram(TRIANGLE)并没有达到您的预期。
将其更改为：
glUseProgram(m_glProgram[TRIANGLE]);