c++ - GLSL uniform ivec 未设置并在被询问时具有默认(错误)值

Question

我有一个包含多个 GLSL 程序 (OpenGL 3.3) 的场景。这些程序使用不同的着色器，它们很相似，但(将)有一些差异。我有一个统一的ivec4 char1，所有版本的名称都相同，它对所有程序具有相同的含义和值(value)。此制服用于 dot1(...) 函数，该函数用于着色器中的 main() 函数。

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);
    }
}

出于某种原因，ivec4 char1 制服已正确设置，可以使用 m_glProgram[GEOMETRY] 和制服 m_glUniform[GEOMETRY_CHAR1] 从第一个着色器中读取，但在带有 m_glProgram[TRIANGLE] 和统一 m_glUniform[PLANE_3D_CHAR1] 的第二个着色器中没有正确设置。这段代码的输出是:

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 

这意味着准备好的 vector [0, 1, 1, 1] 在第一个着色器/程序中正确设置，而不是在第二个中。对其值的查询返回默认值 [0, 0, 0, 0]。这里有什么问题？

Answer 1

如果通过 glUniform4iv 设置统一变量，则着色器程序必须作为当前渲染状态的一部分安装，因为 glUniform4iv 将值设置为当前着色器程序对象的默认统一 block 。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。

这意味着 glUseProgram(TRIANGLE) 没有按照您的预期执行。

将其更改为:

glUseProgram(m_glProgram[TRIANGLE]);