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ComputePositonOffsets（）メソッドとAdjustVertexData（）メソッドを削除することで、単一の三角形を表示できますが、ボタン機能を追加して、画面内に他の場所があるかどうかを確認するためにボタン機能を追加しました。その理由がわかりません。黒い画面を生成します。

#include <algorithm>
#include <string>
#include <vector>
#include <stdio.h>
#include <glload/gl_3_2_comp.h>
#include <GL/freeglut.h>

#define ARRAY_COUNT( array ) (sizeof( array ) / (sizeof( array[0] ) * (sizeof( array ) != sizeof(void*) || sizeof( array[0] ) <= sizeof(void*))))
double rotate_y = 0;
double rotate_x = 0;

GLuint CreateShader(GLenum eShaderType, const std::string &strShaderFile) {
    GLuint shader = glCreateShader(eShaderType);
    const char *strFileData = strShaderFile.c_str();
    glShaderSource(shader, 1, &strFileData, NULL);

    glCompileShader(shader);

    GLint status;
    glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
    if (status == GL_FALSE) {
        GLint infoLogLength;
        glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &infoLogLength);

        GLchar *strInfoLog = new GLchar[infoLogLength + 1];
        glGetShaderInfoLog(shader, infoLogLength, NULL, strInfoLog);

        const char *strShaderType = NULL;
        switch (eShaderType) {
        case GL_VERTEX_SHADER:
            strShaderType = "vertex";
            break;
        case GL_GEOMETRY_SHADER:
            strShaderType = "geometry";
            break;
        case GL_FRAGMENT_SHADER:
            strShaderType = "fragment";
            break;
        }

        fprintf(stderr, "Compile failure in %s shader:\n%s\n", strShaderType,strInfoLog);
        delete[] strInfoLog;
    }

    return shader;
}

GLuint CreateProgram(const std::vector<GLuint> &shaderList) {
    GLuint program = glCreateProgram();

    for (size_t iLoop = 0; iLoop < shaderList.size(); iLoop++)
        glAttachShader(program, shaderList[iLoop]);

    glLinkProgram(program);

    GLint status;
    glGetProgramiv(program, GL_LINK_STATUS, &status);
    if (status == GL_FALSE) {
        GLint infoLogLength;
        glGetProgramiv(program, GL_INFO_LOG_LENGTH, &infoLogLength);

        GLchar *strInfoLog = new GLchar[infoLogLength + 1];
        glGetProgramInfoLog(program, infoLogLength, NULL, strInfoLog);
        fprintf(stderr, "Linker failure: %s\n", strInfoLog);
        delete[] strInfoLog;
    }

    for (size_t iLoop = 0; iLoop < shaderList.size(); iLoop++)
        glDetachShader(program, shaderList[iLoop]);

    return program;
}

GLuint theProgram;

const std::string strVertexShader("#version 330\n"
        "layout(location = 0) in vec4 position;\n"
        "void main()\n"
        "{\n"
        "   gl_Position = position;\n"
        "}\n");

const std::string strFragmentShader("#version 330\n"
        "out vec4 outputColor;\n"
        "void main()\n"
        "{\n"
        "   outputColor = vec4(1.0f, 1.0f, 1.0f, 1.0f);\n"
        "}\n");

void InitializeProgram() {
    std::vector<GLuint> shaderList;

    shaderList.push_back(CreateShader(GL_VERTEX_SHADER, strVertexShader));
    shaderList.push_back(CreateShader(GL_FRAGMENT_SHADER, strFragmentShader));

    theProgram = CreateProgram(shaderList);

    std::for_each(shaderList.begin(), shaderList.end(), glDeleteShader);
}

const float vertexPositions2[] = { 0.5, 0.5, 0.5, -0.5, 0.5, 0.5, -0.5, -0.5,
        0.5, 0.5, -0.5, 0.5, 0.5, 0.5, 0.5, 0.5, -0.5, 0.5, 0.5, 0.5, 0.5, 0.5,
        0.5, -0.5, -0.5, 0.5, -0.5, -0.5, 0.5, 0.5, -0.5, 0.5, 0.5, -0.5, 0.5,
        -0.5, -0.5, -0.5, -0.5, -0.5, -0.5, 0.5, -0.5, -0.5, -0.5, 0.5, -0.5,
        -0.5, 0.5, -0.5, 0.5, -0.5, -0.5, 0.5, 0.5, -0.5, -0.5, -0.5, -0.5,
        -0.5, -0.5, 0.5, -0.5, 0.5, 0.5, -0.5 };

GLuint positionBufferObject;
GLuint vao;

void InitializeVertexBuffer() {
    glGenBuffers(1, &positionBufferObject);

    glBindBuffer(GL_ARRAY_BUFFER, positionBufferObject);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertexPositions2), vertexPositions2,
            GL_STATIC_DRAW);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

//Called after the window and OpenGL are initialized. Called exactly once, before the main loop.
void init() {
    InitializeProgram();
    InitializeVertexBuffer();

    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);
}

void ComputePositionOffsets(float &fXOffset, float &fYOffset) {
    const float fLoopDuration = 5.0f;
    const float fScale = 3.14159f * 2.0f / fLoopDuration;

    float fElapsedTime = glutGet(GLUT_ELAPSED_TIME) / 1000.0f;

    float fCurrTimeThroughLoop = fmodf(fElapsedTime, fLoopDuration);

    fXOffset = cosf(fCurrTimeThroughLoop * fScale) * 0.5f;
    fYOffset = sinf(fCurrTimeThroughLoop * fScale) * 0.5f;
}

void AdjustVertexData(float fXOffset, float fYOffset) {

    std::vector<float> fNewData(ARRAY_COUNT(vertexPositions2));
    memcpy(&fNewData[0], vertexPositions2, sizeof(vertexPositions2));

    for (int iVertex = 0; iVertex < ARRAY_COUNT(vertexPositions2); iVertex +=
            4) {
        fNewData[iVertex] += fXOffset;
        fNewData[iVertex + 1] += fYOffset;
    }

    glBindBuffer(GL_ARRAY_BUFFER, positionBufferObject);
    glBufferSubData(GL_ARRAY_BUFFER, 0, sizeof(vertexPositions2), &fNewData[0]);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

}

//Called to update the display.
//You should call glutSwapBuffers after all of your rendering to display what you rendered.
//If you need continuous updates of the screen, call glutPostRedisplay() at the end of  the function.
void display() {
    glUseProgram(theProgram);
    float fXOffset = 0.0f, fYOffset = 0.0f;
    ComputePositionOffsets(fXOffset, fYOffset);
    AdjustVertexData(fXOffset, fYOffset);
    //glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glLoadIdentity();

    glRotatef(rotate_x, 1.0, 0.0, 0.0);
    glRotatef(rotate_y, 0.0, 1.0, 0.0);

    glBindBuffer(GL_ARRAY_BUFFER, positionBufferObject);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);

    GLubyte indices[] = { 0, 1, 2, 2, 3, 0, 4, 5, 6, 6, 7, 4, 8, 9, 10, 10, 11,
            8, 12, 13, 14, 14, 15, 12, 16, 17, 18, 18, 19, 16, 20, 21, 22, 22,
            23, 20 };    // back

    glDrawElements(GL_TRIANGLES, 36, GL_UNSIGNED_BYTE, indices);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glFlush();
    glUseProgram(0);
    glutSwapBuffers();
}

//Called whenever the window is resized. The new window size is given, in pixels.
//This is an opportunity to call glViewport or glScissor to keep up with the change in size.
void reshape(int w, int h) {
    glViewport(0, 0, (GLsizei) w, (GLsizei) h);
}

//Called whenever a key on the keyboard was pressed.
//The key is given by the ''key'' parameter, which is in ASCII.
//It's often a good idea to have the escape key (ASCII value 27) call glutLeaveMainLoop() to 
//exit the program.
void keyboard(unsigned char key, int x, int y) {
    switch (key) {
    case 27:
        glutLeaveMainLoop();
        return;
    }

    //  Right arrow - increase rotation by 5 degree
    if (key == GLUT_KEY_RIGHT) rotate_y += 5;
    //  Left arrow - decrease rotation by 5 degree
    else if (key == GLUT_KEY_LEFT) rotate_y -= 5;
    else if (key == GLUT_KEY_UP) rotate_x += 5;
    else if (key == GLUT_KEY_DOWN) rotate_x -= 5;

    //  Request display update
    glutPostRedisplay();
}

unsigned int defaults(unsigned int displayMode, int &width, int &height) {
    return displayMode;
}
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1 に答える 1

2 
const float vertexPositions2[] = {0.5,0.5,0.5,-0.5,0.5,0.5,-0.5,-0.5,0.5,0.5,-0.5,0.5,0.5,0.5,0.5,0.5,-0.5,0.5,0.5,0.5,0.5,0.5,0.5,-0.5,-0.5,0.5,-0.5,-0.5,0.5,0.5,-0.5,0.5,0.5,-0.5,0.5,-0.5,-0.5,-0.5,-0.5,-0.5,-0.5,0.5,-0.5,-0.5,-0.5,0.5,-0.5,-0.5,0.5,-0.5,0.5,-0.5,-0.5,0.5,0.5,-0.5,-0.5,-0.5,-0.5,-0.5,-0.5,0.5,-0.5,0.5,0.5,-0.5};

これは立方体を構成する 3D ベクトルのリストであると推測しています.24 (6 面 * 4 コーナー) のインデックスがコードの下部で使用されており、すべての値が 0.5 または -0.5 のいずれかです。ただし、これが 3 つではなく 4 つのコンポーネントを持つベクトルのリストであることを OpenGL に伝えます。

glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);

2 番目のパラメーターを 4 に設定するのは非常に珍しいことです。3 に設定すると、OpenGL によってwコンポーネントが 1 に設定されます。それを試してみてください。そうすれば四角が見えると思います。

これに加えて、透視投影マトリックスがどこにも表示されません。持っていない場合は、3D の代わりに 2D の投影が得られます。物事はあなたが望むようには見えません。回転と移動を実装する前に、それを取得する必要があります。

以下のこれらの行は、プログラムに影響を与えず、最新のグラフィックス プログラムには属しません。それらは、シェーダーで使用しない (GLSL 330 を使用しているため、使用できないと思います) 固定関数マトリックス スタック内のマトリックスを変更します。行列を一様変数として自分で定義する必要があります。

glLoadIdentity();

glRotatef(rotate_x, 1.0, 0.0, 0.0);
glRotatef(rotate_y, 0.0, 1.0, 0.0);
于 2012-11-06T21:57:39.223 に答える