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OpenGL对象的颜色和移动未正确交替

light glm-math glfw opengl c++

Zolly · 技术社区 · 8 年前

我想制作一个“disco”模式,使球体沿x轴左右移动。同时在红色和蓝色之间交替。

g_disco_mode 是选择模式后为真的变量。

static void update_scene()
{
    ...

    // Disco mode
    if (g_disco_mode)
    {
        bool movement_increase = true;
        bool color_increase = true;
        float floor = -0.1f;
        float ceiling = 1.0f;
        float increment = 0.01f;

        // Movement of spotlight
        if (movement_increase == true && g_lightProperties.direction[0] <= ceiling)
        {
            g_lightProperties.direction[0] += increment;

            if (g_lightProperties.direction[0] >= ceiling) { movement_increase = false; }
        }

        if (movement_increase == false && g_lightProperties.direction[0] >= floor)
        {
            g_lightProperties.direction[0] -= increment;

            if (g_lightProperties.direction[0] <= floor) { movement_increase = true; }
        }

        // Changing of color
        g_spotlight_ambient[0] += 0.01f;

        if (color_increase == true && g_spotlight_ambient[0] <= ceiling)
        {
            g_spotlight_ambient[0] += increment;

            if (g_spotlight_ambient[0] >= ceiling) { color_increase = false; }
        }

        if (color_increase == false && g_spotlight_ambient[0] >= floor)
        {
            g_spotlight_ambient[0] -= increment;

            if (g_spotlight_ambient[0] <= floor) { color_increase = true; }
        }   
    }
}

ceiling 然后向左移动,直到碰到 floor g_lightProperties.direction . 颜色的变化也以类似的方式工作。但是,当我运行程序时,球体会向右移动,直到碰到 天花板

我的程序

// Values for spotlight
glm::vec3 g_spotlight_ambient(0.2f, 0.2f, 0.2f);
glm::vec3 g_spotlight_diffuse(0.0f, 0.5f, 1.0f);
glm::vec3 g_spotlight_specular(0.0f, 0.5f, 1.0f);

bool g_switchOn = true;     // toggle the light on/off
bool g_disco_mode = false;  // makes the lights move around and change color

static void init(GLFWwindow* window)
{
    ...

// initialise light and material properties
    g_lightProperties.position = glm::vec4(0.0f, 2.0f, 0.0f, 1.0f);
    g_lightProperties.ambient = glm::vec4(g_spotlight_ambient[0], g_spotlight_ambient[1], g_spotlight_ambient[2], 1.0f);
    g_lightProperties.diffuse = glm::vec4(g_spotlight_diffuse[0], g_spotlight_diffuse[1], g_spotlight_diffuse[2], 1.0f);
    g_lightProperties.specular = glm::vec4(g_spotlight_specular[0], g_spotlight_specular[1], g_spotlight_specular[2], 1.0f);
    g_lightProperties.shininess = 10.0f;
    g_lightProperties.attenuation = glm::vec3(1.0f, 0.0f, 0.0f);
    g_lightProperties.cutoffAngle = 100.0f;
    g_lightProperties.direction = glm::vec3(0.0f, -1.0f, 0.0f);

    ...
}

// function used to update the scene
static void update_scene()
{
    static float rotateAngle = 0.0f;
    static float cutOffAngle = g_lightProperties.cutoffAngle;

    rotateAngle -= 1.0f;

    // update model matrix
    g_modelMatrix_mesh[0] = glm::rotate(glm::radians(rotateAngle), glm::vec3(0.0f, 1.0f, 0.0f))
            * glm::translate(glm::vec3(-0.4f, 0.1f, 0.0f)) * glm::scale(glm::vec3(0.3f, 0.3f, 0.3f));
    g_modelMatrix_mesh[1] = glm::rotate(glm::radians(rotateAngle), glm::vec3(0.0f, 1.0f, 0.0f))
            * glm::translate(glm::vec3(0.4f, 0.3f, 0.0f)) * glm::scale(glm::vec3(0.2f, 0.2f, 0.2f));
    g_modelMatrix_mesh[2] = glm::translate(g_lightProperties.direction)
            * glm::translate(glm::vec3(0.0f, 2.0f, 0.0f)) * glm::scale(glm::vec3(0.2f, 0.2f, 0.2f));

    // update spotlight
    g_lightProperties.ambient = glm::vec4(g_spotlight_ambient[0], g_spotlight_ambient[1], g_spotlight_ambient[2], 1.0f);
    g_lightProperties.diffuse = glm::vec4(g_spotlight_diffuse[0], g_spotlight_diffuse[1], g_spotlight_diffuse[2], 1.0f);
    g_lightProperties.specular = glm::vec4(g_spotlight_specular[0], g_spotlight_specular[1], g_spotlight_specular[2], 1.0f);

    // Disco mode
    if (g_disco_mode)
    {
        bool movement_increase = true;
        bool color_increase = true;
        float floor = -0.1f;
        float ceiling = 1.0f;
        float increment = 0.01f;

        // Movement of spotlight
        if (movement_increase == true && g_lightProperties.direction[0] <= ceiling)
        {
            g_lightProperties.direction[0] += increment;

            if (g_lightProperties.direction[0] >= ceiling) { movement_increase = false; }
        }

        if (movement_increase == false && g_lightProperties.direction[0] >= floor)
        {
            g_lightProperties.direction[0] -= increment;

            if (g_lightProperties.direction[0] <= floor) { movement_increase = true; }
        }

        // Changing of color
        g_spotlight_ambient[0] += 0.01f;

        if (color_increase == true && g_spotlight_ambient[0] <= ceiling)
        {
            g_spotlight_ambient[0] += increment;

            if (g_spotlight_ambient[0] >= ceiling) { color_increase = false; }
        }

        if (color_increase == false && g_spotlight_ambient[0] >= floor)
        {
            g_spotlight_ambient[0] -= increment;

            if (g_spotlight_ambient[0] <= floor) { color_increase = true; }
        }   
    }

}

// function used to render the scene
static void render_scene()
{
    glBindVertexArray(g_VAO[0]);        // make VAO active

// Material Properties - Planes
    glUniform4fv(g_materialAmbientIndex, 1, &g_materialProperties.ambient[0]);
    glUniform4fv(g_materialDiffuseIndex, 1, &g_materialProperties.diffuse[0]);
    glUniform4fv(g_materialSpecularIndex, 1, &g_materialProperties.specular[0]);

    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);
    glUniform3fv(g_lightAttenuationIndex, 1, &g_lightProperties.attenuation[0]);
    glUniform1fv(g_lightCutoffAngleIndex, 1, &g_lightProperties.cutoffAngle);
    glUniform3fv(g_lightDirectionIndex, 1, &g_lightProperties.direction[0]);

    ...
}

int main(void)
{
    TwBar *TweakBar;            // pointer to a tweak bar

    ...

    // initialise AntTweakBar
    TwInit(TW_OPENGL_CORE, NULL);

    // give tweak bar the size of graphics window
    TwWindowSize(g_windowWidth, g_windowHeight);
    TwDefine(" TW_HELP visible=false ");    // disable help menu
    TwDefine(" GLOBAL fontsize=3 ");        // set large font size

    // create a tweak bar
    TweakBar = TwNewBar("Main");
    TwDefine(" Main label='Controls' refresh=0.02 text=light size='220 600' ");

    // create display entries
    TwAddVarRW(TweakBar, "Wireframe", TW_TYPE_BOOLCPP, &g_wireFrame, " group='Display' ");

    // display a separator
    TwAddSeparator(TweakBar, NULL, NULL);

    // create spotlight entries
    TwAddVarRW(TweakBar, "Cutoff", TW_TYPE_FLOAT, &g_lightProperties.cutoffAngle, " group='Spotlight' min=-180.0 max=180.0 step=1.0 ");
    TwAddVarRW(TweakBar, "Direction: x", TW_TYPE_FLOAT, &g_lightProperties.direction[0], " group='Spotlight' min=-1.0 max=1.0 step=0.1");
    TwAddVarRW(TweakBar, "Direction: y", TW_TYPE_FLOAT, &g_lightProperties.direction[1], " group='Spotlight' min=-1.0 max=1.0 step=0.1");
    TwAddVarRW(TweakBar, "Direction: z", TW_TYPE_FLOAT, &g_lightProperties.direction[2], " group='Spotlight' min=-1.0 max=1.0 step=0.1");
    // create transformation entries
    TwAddVarRW(TweakBar, "A Red", TW_TYPE_FLOAT, &g_spotlight_ambient[0], " group='Ambient' min=-1.0 max=1.0 step=0.01");
    TwAddVarRW(TweakBar, "A Green", TW_TYPE_FLOAT, &g_spotlight_ambient[1], " group='Ambient' min=-1.0 max=1.0 step=0.01");
    TwAddVarRW(TweakBar, "A Blue", TW_TYPE_FLOAT, &g_spotlight_ambient[2], " group='Ambient' min=-1.0 max=1.0 step=0.01");

    TwAddVarRW(TweakBar, "D Red", TW_TYPE_FLOAT, &g_spotlight_diffuse[0], " group='Diffuse' min=-1.0 max=1.0 step=0.01");
    TwAddVarRW(TweakBar, "D Green", TW_TYPE_FLOAT, &g_spotlight_diffuse[1], " group='Diffuse' min=-1.0 max=1.0 step=0.01");
    TwAddVarRW(TweakBar, "D Blue", TW_TYPE_FLOAT, &g_spotlight_diffuse[2], " group='Diffuse' min=-1.0 max=1.0 step=0.01");

    TwAddVarRW(TweakBar, "S Red", TW_TYPE_FLOAT, &g_spotlight_specular[0], " group='Specular' min=-1.0 max=1.0 step=0.01");
    TwAddVarRW(TweakBar, "S Green", TW_TYPE_FLOAT, &g_spotlight_specular[1], " group='Specular' min=-1.0 max=1.0 step=0.01");
    TwAddVarRW(TweakBar, "S Blue", TW_TYPE_FLOAT, &g_spotlight_specular[2], " group='Specular' min=-1.0 max=1.0 step=0.01");

    TwAddVarRW(TweakBar, "Light", TW_TYPE_BOOLCPP, &g_switchOn, " group='Toggle ON/OFF' ");
    TwAddVarRW(TweakBar, "Disco", TW_TYPE_BOOLCPP, &g_disco_mode, " group='Toggle ON/OFF' ");

    // initialise rendering states
    init(window);

    // the rendering loop
    while (!glfwWindowShouldClose(window))
    {
        g_camera.update(window);    // update camera

        if (g_wireFrame)
            glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);

        update_scene();     // update the scene
        render_scene();     // render the scene

        glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);

        TwDraw();           // draw tweak bar(s)

        glfwSwapBuffers(window);    // swap buffers
        glfwPollEvents();           // poll for events
    }

    ...
}

1 回复 | 直到 8 年前

Rabbid76 8 年前

或者地板

您的代码应该看起来像这样:

if ( movement_increase )
{   
    // if less than ceiling keep increasing
    movement_increase = g_lightProperties.direction[0] < ceiling; 
}
else
{
    // if less or equal floor change to increasing
    movement_increase = g_lightProperties.direction[0] <= floor;
}
g_lightProperties.direction[0] += movement_increase ? increment : -increment; 

if ( color_increase )
    color_increase = g_spotlight_ambient[0] < 1.0;
else
    color_increase = g_spotlight_ambient[0] <= 0.0;
g_spotlight_ambient[0] += color_increase  ? increment : -increment;

除此之外,变量 movement_increase 和 color_increase static :

 static bool movement_increase = true;
 static bool color_increase = true;