From 7cf879207fdda0af355ce29ff9dceebb010c737e Mon Sep 17 00:00:00 2001
From: hyzboy <hyzboy@gmail.com>
Date: Sat, 8 Dec 2018 15:58:42 +0800
Subject: [PATCH] =?UTF-8?q?=E5=A2=9E=E5=8A=A0SamplerObject=E4=BD=BF?=
 =?UTF-8?q?=E7=94=A8=E8=8C=83=E4=BE=8B=EF=BC=8C=E4=BD=BF=E7=94=A8SamplerOb?=
 =?UTF-8?q?ject=E6=9D=A5=E8=AE=BE=E7=BD=AE=E7=BA=B9=E7=90=86=E8=BF=87?=
 =?UTF-8?q?=E6=BB=A4=E7=AD=89=E5=8F=82=E6=95=B0=EF=BC=8C=E8=80=8C=E9=9D=9E?=
 =?UTF-8?q?=E5=9C=A8=E7=BA=B9=E7=90=86=E4=B8=8A=E8=AE=BE=E7=BD=AE?=
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---
 example/CMakeLists.txt                |   1 +
 example/TextureSampler/CMakeLists.txt |   4 +
 example/TextureSampler/TGATexture.cpp | 153 +++++++++++++++++++
 example/TextureSampler/main.cpp       | 212 ++++++++++++++++++++++++++
 4 files changed, 370 insertions(+)
 create mode 100644 example/TextureSampler/CMakeLists.txt
 create mode 100644 example/TextureSampler/TGATexture.cpp
 create mode 100644 example/TextureSampler/main.cpp

diff --git a/example/CMakeLists.txt b/example/CMakeLists.txt
index 1e07a0d2..4ff09480 100644
--- a/example/CMakeLists.txt
+++ b/example/CMakeLists.txt
@@ -3,4 +3,5 @@ add_subdirectory(OutputGLInfo)
 add_subdirectory(NullWindow)
 add_subdirectory(DirectGLRender)
 add_subdirectory(DirectGLTexture)
+add_subdirectory(TextureSampler)
 # add_subdirectory(DrawTriangle)
diff --git a/example/TextureSampler/CMakeLists.txt b/example/TextureSampler/CMakeLists.txt
new file mode 100644
index 00000000..7d1c0fd9
--- /dev/null
+++ b/example/TextureSampler/CMakeLists.txt
@@ -0,0 +1,4 @@
+add_executable(TextureSampler main.cpp TGATexture.cpp)
+
+target_link_libraries(TextureSampler PRIVATE ${ULRE})
+
diff --git a/example/TextureSampler/TGATexture.cpp b/example/TextureSampler/TGATexture.cpp
new file mode 100644
index 00000000..d91c0850
--- /dev/null
+++ b/example/TextureSampler/TGATexture.cpp
@@ -0,0 +1,153 @@
+#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,GLuint &tex_id)
+        {
+            std::ifstream file;
+
+            file.open(filename,std::ifstream::in|std::ifstream::binary);
+
+            if(!file.is_open())
+            {
+                std::cerr<<"[ERROR] open file<"<<filename.c_str()<<"> 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;
+            uint line_size=0;
+
+            if(header->image_type==2)
+            {
+                if(header->bit==24)
+                {
+                    videomemory_format=GL_RGB8;
+                    source_format=GL_BGR;
+                    line_size=header->width*3;
+                }
+                else if(header->bit==32)
+                {
+                    videomemory_format=GL_RGBA8;
+                    source_format=GL_BGRA;
+                    line_size=header->width*4;
+                }
+            }
+            else if(header->image_type==3&&header->bit==8)
+            {
+                videomemory_format=GL_R8;
+                source_format=GL_RED;
+                line_size=header->width;
+            }
+            else
+            {
+                std::cerr<<"[ERROR] Image format error,filename: "<<filename.c_str()<<std::endl;
+                delete[] data;
+                return(false);
+            }
+
+            glCreateTextures(GL_TEXTURE_2D,1,&tex_id);
+
+            glTextureStorage2D(tex_id,1,videomemory_format,header->width,header->height);
+
+            TGAImageDesc img_desc;
+
+            img_desc.image_desc=header->image_desc;
+
+            if(img_desc.direction==1)
+                glTextureSubImage2D(tex_id,0,0,0,header->width,header->height,source_format,GL_UNSIGNED_BYTE,data+sizeof(TGAHeader));
+            else
+            {
+                char *new_img=new char[line_size*header->height];
+                char *sp=data+sizeof(TGAHeader)+line_size*(header->height-1);
+                char *tp=new_img;
+
+                for(int i=0;i<header->height;i++)
+                {
+                    memcpy(tp,sp,line_size);
+                    tp+=line_size;
+                    sp-=line_size;
+                }
+
+                glTextureSubImage2D(tex_id,0,0,0,header->width,header->height,source_format,GL_UNSIGNED_BYTE,new_img);
+                delete[] new_img;
+            }
+
+            glGenerateTextureMipmap(tex_id);
+
+            std::cout<<"load image file<"<<filename.c_str()<<">:<"<<header->width<<"x"<<header->height<<"> to texture ok"<<std::endl;
+
+            delete[] data;
+            return(true);
+        }
+
+        GLuint CreateSamplerObject(GLint min_filter,GLint mag_filter,GLint clamp,const GLfloat *border_color)
+        {
+            GLuint sampler_object;
+
+            glGenSamplers(1,&sampler_object);
+
+            glSamplerParameteri(sampler_object,GL_TEXTURE_MIN_FILTER,min_filter);
+            glSamplerParameteri(sampler_object,GL_TEXTURE_MAG_FILTER,mag_filter);
+            glSamplerParameteri(sampler_object,GL_TEXTURE_WRAP_S,clamp);
+            glSamplerParameteri(sampler_object,GL_TEXTURE_WRAP_T,clamp);
+
+            glSamplerParameterfv(sampler_object,GL_TEXTURE_BORDER_COLOR,border_color);
+
+            return(sampler_object);
+        }
+    }//namespace graph
+}//namespace hgl
diff --git a/example/TextureSampler/main.cpp b/example/TextureSampler/main.cpp
new file mode 100644
index 00000000..605a9fab
--- /dev/null
+++ b/example/TextureSampler/main.cpp
@@ -0,0 +1,212 @@
+#include<hgl/graph/RenderDevice.h>
+#include<hgl/graph/RenderDriver.h>
+#include<hgl/graph/RenderWindow.h>
+#include<iostream>
+#include<GLEWCore/glew.h>
+#include<hgl/graph/Shader.h>
+#include<hgl/math/Math.h>
+#include<hgl/graph/VertexArray.h>
+
+using namespace hgl;
+using namespace hgl::graph;
+
+constexpr uint screen_width=640;
+constexpr uint screen_height=640;
+
+GLuint texture_id=0;
+GLuint sampler_id=0;
+
+namespace hgl
+{
+    namespace graph
+    {
+        bool LoadTGATexture(const std::string &filename,GLuint &tex_id);
+        GLuint CreateSamplerObject(GLint min_filter,GLint mag_filter,GLint clamp,const GLfloat *border_color);
+    }
+}
+
+constexpr char vertex_shader[]=R"(
+#version 330 core
+
+in vec2 Vertex;
+in vec2 TexCoord;
+
+out vec2 FragmentTexCoord;
+
+void main()
+{
+    FragmentTexCoord=TexCoord;
+
+    gl_Position=vec4(Vertex,0.0,1.0);
+})";
+
+constexpr char fragment_shader[]=R"(
+#version 330 core
+
+uniform sampler2D TextureLena;
+
+in vec2 FragmentTexCoord;
+out vec4 FragColor;
+
+void main()
+{
+    FragColor=texture(TextureLena,FragmentTexCoord);
+})";
+
+Shader shader;
+
+bool InitShader()
+{
+    if(!shader.AddVertexShader(vertex_shader))
+        return(false);
+
+    if(!shader.AddFragmentShader(fragment_shader))
+        return(false);
+
+    if(!shader.Build())
+        return(false);
+
+    if(!shader.Use())
+        return(false);
+
+    return(true);
+}
+
+VB2f *vb_vertex=nullptr;
+VB2f *vb_texcoord=nullptr;
+VertexArray *va=nullptr;
+
+constexpr float vertex_data[]={ -0.75f, 0.75f,
+                                -0.75f,-0.75f,
+                                 0.75f, 0.75f,
+                                 0.75f,-0.75f
+};
+
+constexpr float texcoord_data[]={   -0.25,-0.25,
+                                    -0.25, 1.25,
+                                     1.25,-0.25,
+                                     1.25, 1.25   };
+
+
+void BindVBO2VAO(const int vao,const int binding_index,const int shader_location,VertexBufferBase *vb)
+{
+    glVertexArrayAttribBinding(vao,shader_location,binding_index);
+    glVertexArrayAttribFormat(vao,shader_location,vb->GetComponent(),vb->GetDataType(),GL_FALSE,0);
+    glEnableVertexArrayAttrib(vao,shader_location);
+    glVertexArrayVertexBuffer(vao,binding_index,vb->GetBufferIndex(),0,vb->GetStride());
+}
+
+void InitVertexBuffer()
+{
+    vb_vertex=new VB2f(4,vertex_data);
+    vb_texcoord=new VB2f(4,texcoord_data);
+
+    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
+
+    int binding_index=0;                    //绑定点
+
+    const int vao=va->GetVAO();
+
+    va->SetVertexBuffer(vb_vertex);
+    va->AddVertexAttribBuffer(vb_texcoord);
+
+    BindVBO2VAO(vao,binding_index,vertex_location,vb_vertex);
+    ++binding_index;
+    BindVBO2VAO(vao,binding_index,texcoord_location,vb_texcoord);
+}
+
+bool InitTexture()
+{
+    if(!LoadTGATexture("lena.tga",texture_id))
+        return(false);
+
+    const GLfloat border_color[4]={1,1,0,1};
+
+    sampler_id=CreateSamplerObject(GL_NEAREST_MIPMAP_NEAREST, GL_NEAREST, GL_CLAMP_TO_BORDER,border_color);
+
+    int texture_location=shader.GetUniformLocation("TextureLena");
+
+    glBindTextureUnit(0,texture_id);
+    glBindSampler(0,sampler_id);
+
+    shader.SetUniform1i(texture_location,0);
+
+    return(true);
+}
+
+constexpr GLfloat clear_color[4]=
+{
+    77.f/255.f,
+    78.f/255.f,
+    83.f/255.f,
+    1.f
+};
+
+constexpr GLfloat clear_depth=1.0f;
+
+void draw()
+{
+    glClearBufferfv(GL_COLOR,0,clear_color);
+    glClearBufferfv(GL_DEPTH,0,&clear_depth);
+
+    va->Draw();
+}
+
+int main(void)
+{
+    RenderDevice *device=CreateRenderDeviceGLFW();
+
+    if(!device)
+    {
+        std::cerr<<"Create RenderDevice(GLFW) failed."<<std::endl;
+        return -1;
+    }
+
+    if(!device->Init())
+    {
+        std::cerr<<"Init RenderDevice(GLFW) failed."<<std::endl;
+        return -2;
+    }
+
+    WindowSetup ws;
+
+    ws.Name=U8_TEXT("Direct use \"OpenGL Core API\" Render");
+
+    RenderSetup rs;
+
+    RenderWindow *win=device->Create(screen_width,screen_height,&ws,&rs);
+
+    win->MakeToCurrent();               //切换当前窗口到前台
+
+    InitOpenGLDebug();                  //初始化OpenGL调试输出
+
+    if(!InitShader())
+    {
+        std::cerr<<"init shader failed."<<std::endl;
+        return -3;
+    }
+
+    InitVertexBuffer();
+
+    if(!InitTexture())
+        return -4;
+
+    win->Show();
+
+    while(win->IsOpen())
+    {
+        draw();
+
+        win->SwapBuffer();              //交换前后台显示缓冲区
+        win->PollEvent();               //处理窗口事件
+    }
+
+    delete win;
+    delete device;
+
+    return 0;
+}