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hereからデモをダウンロードしました。xcode で glewInit() を削除し、他のすべては同じままにしました。エラーも警告もなしに実行しましたが、出力はすべてゼロです。なぜですか?

私の mac: OS X EI キャプテン、Intel Iris Graphics 6100

デモは次のとおりです。

#include "basicFeedBack.hpp"
#include "stdio.h"
#include <SFML/Window.hpp>
#include <OpenGL/gl3.h>
#include <OpenGL/glu.h>
#include <GLUT/glut.h>

// Shader macro
#define GLSL(src) "#version 150 core\n" #src

// Vertex shader
const GLchar* vertexShaderSrc = GLSL(
                                     in float inValue;
                                     out float outValue;

                                     void main() {
                                         outValue = sqrt(inValue);
                                     }
                                     );

int main() {
    // Window
    sf::ContextSettings settings;
    settings.depthBits = 24;
    settings.stencilBits = 8;

    sf::Window window(sf::VideoMode(800, 600), "Transform Feedback", sf::Style::Titlebar | sf::Style::Close, settings);


    // Compile shader
    GLuint shader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(shader, 1, &vertexShaderSrc, 0);
    glCompileShader(shader);

    // Create program and specify transform feedback variables
    GLuint program = glCreateProgram();
    glAttachShader(program, shader);

    const GLchar* feedbackVaryings[] = { "outValue" };
    glTransformFeedbackVaryings(program, 1, feedbackVaryings, GL_INTERLEAVED_ATTRIBS);

    glLinkProgram(program);
    glUseProgram(program);

    // Create VAO
    GLuint vao;
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);

    // Create input VBO and vertex format
    GLfloat data[] = { 1.0f, 2.0f, 3.0f, 4.0f, 5.0f };

    GLuint vbo;
    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(data), data, GL_STATIC_DRAW);

    GLint inputAttrib = glGetAttribLocation(program, "inValue");
    glEnableVertexAttribArray(inputAttrib);
    glVertexAttribPointer(inputAttrib, 1, GL_FLOAT, GL_FALSE, 0, 0);

    // Create transform feedback buffer
    GLuint tbo;
    glGenBuffers(1, &tbo);
    glBindBuffer(GL_ARRAY_BUFFER, tbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(data), nullptr, GL_STATIC_READ);

    // Perform feedback transform
    glEnable(GL_RASTERIZER_DISCARD);

    glBindBufferBase(GL_TRANSFORM_FEEDBACK_BUFFER, 0, tbo);

    glBeginTransformFeedback(GL_POINTS);
    glDrawArrays(GL_POINTS, 0, 5);
    glEndTransformFeedback();

    glDisable(GL_RASTERIZER_DISCARD);

    glFlush();

    // Fetch and print results
    GLfloat feedback[5];
    glGetBufferSubData(GL_TRANSFORM_FEEDBACK_BUFFER, 0, sizeof(feedback), feedback);

    printf("%f %f %f %f %f\n", feedback[0], feedback[1], feedback[2], feedback[3], feedback[4]);

    return 0;
}

私の出力：

0.000000 0.000000 0.000000 0.000000 0.000000
4

1 に答える 1