完成绘制纹理矩形范例

example/DirectGLTexture/CMakeLists.txt

@@ -1,4 +1,4 @@
-add_executable(DirectGLTexture main.cpp)
+add_executable(DirectGLTexture main.cpp TGATexture.cpp)
 
 target_link_libraries(DirectGLTexture PRIVATE ${ULRE})
 

example/DirectGLTexture/TGATexture.cpp

@@ -0,0 +1,114 @@
+#include<GLEWCore/glew.h>
+#include<hgl/type/DataType.h>
+#include<fstream>
+#include<iostream>
+
+namespace hgl
+{
+    namespace graph
+    {
+        namespace
+        {
+            #pragma pack(push,1)
+            struct TGAHeader
+            {
+                uint8 id;
+                uint8 color_map_type;
+                uint8 image_type;               // 1 colormap image ,2 true-color,3 grayscale
+
+                uint16 color_map_first;
+                uint16 color_map_length;
+                uint8 color_map_size;
+
+                uint16 x_origin;
+                uint16 y_origin;
+
+                uint16 width;
+                uint16 height;
+                uint8 bit;
+
+                uint8 image_desc;
+            };
+
+            union TGAImageDesc
+            {
+                //不要把此union放到上面的struct中，否则Visual C++会将此union编译成4字节。GCC无此问题
+                uint8 image_desc;
+                struct
+                {
+                    uint alpha_depth:4;
+                    uint reserved:1;
+                    uint direction:1;       //0 lower-left,1 upper left
+                };
+            };
+            #pragma pack(pop)
+        }//namespace
+
+        bool LoadTGATexture(const std::string &filename,uint &tex_id)
+        {
+            std::ifstream file;
+
+            file.open(filename,std::ifstream::in|std::ifstream::binary);
+
+            if(!file.is_open())
+            {
+                std::cerr<<"[ERROR] open file<"<<filename<<"> failed."<<std::endl;
+                return(false);
+            }
+
+            file.seekg(0,std::ifstream::end);
+            const int file_length=file.tellg();
+
+            char *data=new char[file_length];
+
+            file.seekg(0,std::ifstream::beg);
+            file.read(data,file_length);
+            file.close();
+
+            TGAHeader *header=(TGAHeader *)data;
+
+            uint videomemory_format;
+            uint source_format;
+
+            if(header->image_type==2)
+            {
+                if(header->bit==24)
+                {
+                    videomemory_format=GL_RGB8;
+                    source_format=GL_BGR;
+                }
+                else if(header->bit==32)
+                {
+                    videomemory_format=GL_RGBA8;
+                    source_format=GL_BGRA;
+                }
+            }
+            else if(header->image_type==3&&header->bit==8)
+            {
+                videomemory_format=GL_R8;
+                source_format=GL_RED;
+            }
+            else
+            {
+                std::cerr<<"[ERROR] Image format error,filename: "<<filename<<std::endl;
+                delete[] data;
+                return(false);
+            }
+
+            glCreateTextures(GL_TEXTURE_2D,1,&tex_id);
+
+            glTextureStorage2D(tex_id,1,videomemory_format,header->width,header->height);
+            glTextureSubImage2D(tex_id,0,0,0,header->width,header->height,source_format,GL_UNSIGNED_BYTE,data+sizeof(TGAHeader));
+
+            glTextureParameteri(tex_id,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
+            glTextureParameteri(tex_id,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
+            glTextureParameteri(tex_id,GL_TEXTURE_WRAP_S,GL_CLAMP_TO_EDGE);
+            glTextureParameteri(tex_id,GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE);
+
+            std::cout<<"load image file<"<<filename<<">:<"<<header->width<<"x"<<header->height<<"> to texture ok"<<std::endl;
+
+            delete[] data;
+            return(true);
+        }
+    }//namespace graph
+}//namespace hgl

example/DirectGLTexture/main.cpp

@@ -10,9 +10,19 @@
 using namespace hgl;
 using namespace hgl::graph;
 
-constexpr uint screen_width=1280;
+constexpr uint screen_width=720;
 constexpr uint screen_height=720;
 
+uint texture_id=0;
+
+namespace hgl
+{
+    namespace graph
+    {
+        bool LoadTGATexture(const std::string &filename,uint &tex_id);
+    }
+}
+
 constexpr char vertex_shader[]=R"(
 #version 330 core
 
@@ -31,14 +41,14 @@ void main()
 constexpr char fragment_shader[]=R"(
 #version 330 core
 
-sampler2D Texture0;
+uniform sampler2D TextureLuna;
 
-in vec4 FragmentTexCoord;
+in vec2 FragmentTexCoord;
 out vec4 FragColor;
 
 void main()
 {
-    FragColor=vec4(FragmentColor.rgb,1);
+    FragColor=texture(TextureLuna,FragmentTexCoord);
 })";
 
 Shader shader;
@@ -89,8 +99,8 @@ void InitVertexBuffer()
     vb_vertex=new VB2f(4,vertex_data);
     vb_texcoord=new VB2f(4,texcoord_data);
 
-    va=new VertexArray(GL_TRIANGLES,        //画三角形
-                        2);                  //两个属性
+    va=new VertexArray(GL_TRIANGLE_STRIP,       //画三角形条
+                        2);                     //两个属性
 
     const int vertex_location=shader.GetAttribLocation("Vertex");              ///<取得顶点数据输入流对应的shader地址
     const int texcoord_location=shader.GetAttribLocation("TexCoord");             ///<取得纹理坐标数据输入流对应的shader地址
@@ -107,6 +117,20 @@ void InitVertexBuffer()
     BindVBO2VAO(vao,binding_index,texcoord_location,vb_texcoord);
 }
 
+bool InitTexture()
+{
+    if(!LoadTGATexture("luna.tga",texture_id))
+        return(false);
+
+    int texture_location=shader.GetUniformLocation("TextureLuna");
+
+    glBindTextureUnit(0,texture_id);
+
+    shader.SetUniform1i(texture_location,0);
+
+    return(true);
+}
+
 constexpr GLfloat clear_color[4]=
 {
     77.f/255.f,
@@ -161,6 +185,9 @@ int main(void)
 
     InitVertexBuffer();
 
+    if(!InitTexture())
+        return -4;
+
     win->Show();
 
     while(win->IsOpen())