一步步写水面渲染（二）

第六步：计算纹理坐标

struct DATAS
{
GLfloat vertex_data[3];
GLfloat normal_data[3];
GLfloat texcoord_data[2];
}VBOdata[DATA_LENGTH];

//先前，我是直接用两个数组来存储位置和法线数据，现在为了在传递数据时便于计算，我用一个结构体来存储一个顶点的所有信息

int pt;
for (int c = 0; c<(STRIP_COUNT - 1); c++)
{
for (int l = 0; l<2 * STRIP_LENGTH; l++)
{
if (l % 2 == 1)
{
pt = c*STRIP_LENGTH + l / 2;
}
else
{
pt = c*STRIP_LENGTH + l / 2 + STRIP_LENGTH;
}
index = STRIP_LENGTH * 2 * c + l;
for (int i = 0; i<3; i++)
{
VBOdata[index].vertex_data[i] = pt_strip[pt * 3 + i];
VBOdata[index].normal_data[i] = pt_normal[pt * 3 + i];
if (i < 2)
VBOdata[index].texcoord_data[i] = (pt_strip[pt * 3 + i] + 1)/2;
}
}
}
//上述是修改后的对顶点进行排序的代码
//因为我的顶点位置坐标的值在[-1,1]范围内，且我偷懒直接对整个海面用一张纹理贴图，又因为纹理坐标的值在[0,1]的范围内，所以我直接将位置坐标中的x轴坐标和y轴坐标通过+1再除以2的方式将其改变为[0,1]的区间范围中。

//接下来更改一下传递数据的代码
void RenderWater()
{
glBindVertexArray(VAO);

glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(VBOdata), VBOdata, GL_STATIC_DRAW);

glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)0);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
glEnableVertexAttribArray(2);
glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(GLfloat), (GLvoid*)(6 * sizeof(GLfloat)));

glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);

glBindVertexArray(VAO);
for (int c = 0; c<(STRIP_COUNT - 1); c++)
glDrawArrays(GL_TRIANGLE_STRIP, STRIP_LENGTH * 2 * c, STRIP_LENGTH * 2);
glBindVertexArray(0);
}

第七步：vertexshader

#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoords;

out VS_OUT
{
vec3 FragPos;
vec3 Normal;
vec2 TexCoords;
} vs_out;

uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;

void main()
{
gl_Position = projection * view * model * vec4(position, 1.0f);
vs_out.FragPos = position;
vs_out.Normal = normal;
vs_out.TexCoords = texCoords;
}

第八步：fragmentshader

//这里采用了Blinn-Phong光照模型
#version 330 core
out vec4 FragColor;

in VS_OUT
{
vec3 FragPos;
vec3 Normal;
vec2 TexCoords;
} fs_in;

uniform sampler2D floorTexture;
uniform vec3 lightPos;
uniform vec3 viewPos;

void main()
{
vec3 color = texture(floorTexture, fs_in.TexCoords).rgb;

vec3 ambient = 0.05 * color;

vec3 lightDir = normalize(lightPos - fs_in.FragPos);
vec3 normal = normalize(fs_in.Normal);
float diff = max(dot(lightDir, normal), 0.0);
vec3 diffuse = diff * color;

vec3 viewDir = normalize(viewPos - fs_in.FragPos);
vec3 reflectDir = reflect(-lightDir, normal);
float spec = 0.0;

vec3 halfwayDir = normalize(lightDir + viewDir);
spec = pow(max(dot(normal, halfwayDir), 0.0), 32.0);

vec3 specular = vec3(0.3) * spec; // assuming bright white light color
FragColor = vec4(ambient + diffuse + specular, 1.0f);
}