Now it’s time to think where to get actual 3D models for our Project. Our options are:<\/p>\n\n\n\n
So, let’s start with the last option – generate models programmatically<\/em>. It will be a set of tools and classes, a considerable part of our engine. Let’s create a placeholder for it.<\/p>\n\n\n\n 1. In Windows File Explorer<\/strong> under C:\\CPP\\engine<\/em> folder create a new sub-folder modeler<\/strong>.<\/p>\n\n\n\n 2. Go to C:\\CPP<\/em> folder. Make a copy of a998engine <\/em>and name it a997modeler<\/strong>.<\/p>\n\n\n\n 3. Start VS. Open C:\\CPP\\a997modeler<\/strong>\\p_windows\\p_windows.sln<\/em>.<\/p>\n\n\n\n Under xEngine <\/em>(right-click on xEngine <\/em>) add New Filter<\/strong>, call it modeler<\/strong>.<\/p>\n\n\n\n 4. Add a reference to new folder: <\/p>\n\n\n\n Open p_windows<\/em> project Properties. All Configurations \/ Active(Win32), <\/p>\n\n\n\n C\/C++ -> General -> Additional Include Directories -> Edit<\/em>, add a new line, <\/p>\n\n\n\n browse to C:\\CPP\\engine\\modeler<\/em>, <\/p>\n\n\n\n Select Folder, Ok, Apply, Ok.<\/p>\n\n\n\n The idea of the “modeler” is to build an array of vertices and indices and then convert them to VBOs, EBOs, VAOs and DrawJobs.<\/p>\n\n\n\n 5. Add the first class, Vertex01<\/strong>. As usual, file-by-file:<\/p>\n\n\n\n Under modeler <\/em>add new header file Vertex01.h<\/strong><\/p>\n\n\n\n Location – C:\\CPP\\engine\\modeler<\/em><\/p>\n\n\n\n Code:<\/p>\n\n\n <\/p>\n\n\n\n Don’t worry about extra variables, will explain them later, as we use them. Don’t need cpp <\/em>file yet.<\/p>\n\n\n\n Since we are planning to use indexes (EBO) to draw triangles arrays, we’ll need a placeholder for them.<\/p>\n\n\n\n 6. Under modeler <\/em>add new header file Triangle01.h<\/strong><\/p>\n\n\n\n Location – C:\\CPP\\engine\\modeler<\/em><\/p>\n\n\n\n Code:<\/p>\n\n\n <\/p>\n\n\n\n Same here, don’t worry about extra variables, will explain them later, as we use them.<\/p>\n\n\n\n Also we’ll need vertices\/triangles groups for various manipulations.<\/p>\n\n\n\n 7, Under modeler <\/em>add new header file Group01.h<\/strong><\/p>\n\n\n\n Location – C:\\CPP\\engine\\modeler<\/em><\/p>\n\n\n\n Code:<\/p>\n\n\n <\/p>\n\n\n\n We mostly need to know where\/when the current group started, that’s why there is no “to” variables.<\/p>\n\n\n\n Besides, we’ll need some kind of descriptor of which shape we are drawing\/building. I’ll call it VirtualShape<\/strong>. “Virtual” because it won’t create any actual vertices by itself.<\/p>\n\n\n\n 8. Under modeler <\/em>add new header file VirtualShape.h<\/strong><\/p>\n\n\n\n Location – C:\\CPP\\engine\\modeler<\/em><\/p>\n\n\n\n Code:<\/p>\n\n\n <\/p>\n\n\n\n The key operation\/command of the modeler <\/em>will be buildFace()<\/em>. let’s say “on the left side of current VirtualShape<\/em>“. This command will create 4 actual vertices on the left side of the shape (in this sample – of the box with whl <\/em>dimensions) and 2 corresponding triangle indices (6 indices total).<\/p>\n\n\n\n Some calculations we’ll move to utils <\/strong>set.<\/p>\n\n\n\n 9. Open utils.h<\/em> and replace code by:<\/p>\n\n\n <\/p>\n\n\n\n 10. Open utils.cpp and replace code by:<\/p>\n\n\n <\/p>\n\n\n\n This new mat4x4_mul_vec4plus()<\/em> function is a vector\/matrix multiplication. The difference from linmath <\/em>function is that it avoids writing result to the argument vector, plus it overwrites the last position of the argument vector. If it’s 0, the resulting vector will ignore position part of the transform matrix, so it will be just a direction (used for rotating normals <\/em>for example).<\/p>\n\n\n\n Also need to extend DrawJob<\/strong><\/p>\n\n\n\n 11. Open DrawJob.h<\/em> and replace code by:<\/p>\n\n\n <\/p>\n\n\n\n This new setDesirableOffsets..()<\/em> function fills out DrawJob’s<\/em> attribute references (AttribRef aPos<\/em> and aTuv<\/em>, later we will have more attributes).<\/p>\n\n\n\n 12. Open DrawJob.cpp<\/em> and replace code by: <\/p>\n\n\n <\/p>\n\n\n\n To be continued…<\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Now it’s time to think where to get actual 3D models for our Project. Our options are: So, let’s start with the last option – generate models programmatically. It will be a set of tools and classes, a considerable part of our engine. Let’s create a placeholder for it. 1. In Windows File Explorer under […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[],"class_list":["post-546","post","type-post","status-publish","format-standard","hentry","category-cross-platform-3d"],"_links":{"self":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts\/546","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/comments?post=546"}],"version-history":[{"count":24,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts\/546\/revisions"}],"predecessor-version":[{"id":1960,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/posts\/546\/revisions\/1960"}],"wp:attachment":[{"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/media?parent=546"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/categories?post=546"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/writingagame.com\/index.php\/wp-json\/wp\/v2\/tags?post=546"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
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\n\n\n\n\n#pragma once\n\nclass Vertex01\n{\npublic:\n\tint subjN = -1; \/\/game subject number\n\tint materialN = -1; \/\/material number\n\tint flag = 0;\n\tint endOfSequence = 0; \/\/for sequentional (unindexed) primitives (like GL_LINE_STRIP for example)\n\tint altN = -1; \/\/vertex' position in alternative array\n\t\/\/atributes\n\tfloat aPos[4] = { 0,0,0,0 }; \/\/position x,y,z + 4-th float for matrix operations\n\tfloat aNormal[4] = { 0,0,0,0 }; \/\/normal (surface reflection vector) x,y,z + 4-th float for matrix operations\n\tfloat aTuv[2] = { 0,0 }; \/\/2D texture coordinates\n\tfloat aTuv2[2] = { 0,0 }; \/\/for normal maps\n\t\/\/tangent space (for normal maps)\n\tfloat aTangent[3] = { 0,0,0 };\n\tfloat aBinormal[3] = { 0,0,0 };\n};\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#pragma once\n\nclass Triangle01\n{\npublic:\n\tint subjN = -1; \/\/game subject number\n\tint materialN = -1; \/\/material number\n\tint flag = 0;\n\tint idx[3] = { 0,0,0 }; \/\/3 vertex indices\n};\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#pragma once\n\nclass Group01\n{\npublic:\n\tint fromVertexN = 0;\n\tint fromTriangleN = 0;\n};\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#pragma once\n#include <string>\n\nclass VirtualShape\n{\npublic:\n\tstd::string type = "box";\n\tfloat whl[3] = { 0 }; \/\/width\/height\/length (x,y,z sizes\/dimensions)\n};\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#pragma once\n#include <string>\n#include "linmath.h"\n\nint checkGLerrors(std::string ref);\nvoid mat4x4_mul_vec4plus(vec4 vOut, mat4x4 M, vec4 vIn, int v3);\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#include "utils.h"\n#include "platform.h"\n\nint checkGLerrors(std::string ref) {\n \/\/can be used after any GL call\n int res = glGetError();\n if (res == 0)\n return 0;\n std::string errCode;\n switch (res) {\n \/\/case GL_NO_ERROR: errCode = "GL_NO_ERROR"; break;\n case GL_INVALID_ENUM: errCode = "GL_INVALID_ENUM"; break;\n case GL_INVALID_VALUE: errCode = "GL_INVALID_VALUE"; break;\n case GL_INVALID_OPERATION: errCode = "GL_INVALID_OPERATION"; break;\n case GL_INVALID_FRAMEBUFFER_OPERATION: errCode = "GL_INVALID_FRAMEBUFFER_OPERATION"; break;\n case GL_OUT_OF_MEMORY: errCode = "GL_OUT_OF_MEMORY"; break;\n default: errCode = "??"; break;\n }\n mylog("GL ERROR %d-%s in %s\\n", res, errCode.c_str(), ref.c_str());\n return -1;\n}\nvoid mat4x4_mul_vec4plus(vec4 vOut, mat4x4 M, vec4 vIn, int v3) {\n vec4 v2;\n if (vOut == vIn) {\n memcpy(&v2, vIn, sizeof(vec4));\n vIn = v2;\n }\n vIn[3] = (float)v3;\n mat4x4_mul_vec4(vOut, M, vIn);\n}\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#pragma once\n#include "Material.h"\n#include <vector>\n\nstruct AttribRef \/\/attribute reference\/description\n{\n\tunsigned int glVBOid = 0; \/\/buffer object id\n\tint offset = 0; \/\/variable's offset inside of VBO's element\n\tint stride = 0; \/\/Buffer's element size in bytes\n};\n\nclass DrawJob\n{\npublic:\n\tMaterial mt;\n\tint pointsN = 0; \/\/N of points to draw\n\tunsigned int glVAOid = 0; \/\/will hold data stream attributes mapping\/positions\n\tunsigned int glEBOid = 0; \/\/Element Buffer Object (vertex indices)\n\n\t\/\/common attributes\n\tAttribRef aPos;\n\tAttribRef aTuv;\n\n\t\/\/static arrays (vectors) of all loaded DrawJobs, VBO ids\n\tstatic std::vector<DrawJob*> drawJobs;\n\tstatic std::vector<unsigned int> buffersIds;\npublic:\n\tDrawJob();\n\tvirtual ~DrawJob(); \/\/destructor\n\tstatic int cleanUp();\n\tstatic int newBufferId();\n\tint buildVAO() { return buildVAOforShader(this, mt.shaderN); };\n\tstatic int buildVAOforShader(DrawJob* pDJ, int shaderN);\n\tstatic int attachAttribute(int varLocationInShader, int attributeSizeInFloats, AttribRef* pAttribRef);\n\n\tvirtual int setDesirableOffsets(int* pStride, int shaderN, int VBOid) { return setDesirableOffsetsForSingleVBO(this, pStride, shaderN, VBOid); };\n\tstatic int setDesirableOffsetsForSingleVBO(DrawJob* pDJ, int* pStride, int shaderN, int VBOid);\n\n\tint execute(float* uMVP, Material* pMt) { return executeDrawJob(this, uMVP, pMt); };\n\tstatic int executeDrawJob(DrawJob* pDJ, float* uMVP, Material* pMt);\n};\n\n<\/pre><\/div>\n\n\n
\n\n\n\n\n#include "DrawJob.h"\n#include "platform.h"\n#include "utils.h"\n#include "Shader.h"\n#include "Texture.h"\n\n\/\/static arrays (vectors) of all loaded DrawJobs, VBO ids\nstd::vector<DrawJob*> DrawJob::drawJobs;\nstd::vector<unsigned int> DrawJob::buffersIds;\n\nDrawJob::DrawJob() {\n\tdrawJobs.push_back(this);\n}\nDrawJob::~DrawJob() {\n\tglBindBuffer(GL_ARRAY_BUFFER, 0);\n\tglBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);\n\tif (glVAOid > 0)\n\t\tglDeleteVertexArrays(1, &glVAOid);\n}\nint DrawJob::newBufferId() {\n\tunsigned int bufferId;\n\tglGenBuffers(1, &bufferId);\n\tbuffersIds.push_back(bufferId);\n\treturn (int)bufferId;\n}\nunsigned int activeVBOid;\nint DrawJob::buildVAOforShader(DrawJob* pDJ, int shaderN) {\n\t\/\/delete VAO if exists already\n\tif (pDJ->glVAOid > 0) {\n\t\tglBindBuffer(GL_ARRAY_BUFFER, 0);\n\t\tglDeleteVertexArrays(1, &(pDJ->glVAOid));\n\t}\n\tglGenVertexArrays(1, &pDJ->glVAOid);\n\tglBindVertexArray(pDJ->glVAOid);\n\n\t\/\/open shader descriptor to access variables locations\n\tShader* pShader = Shader::shaders.at(pDJ->mt.shaderN);\n\n\tactiveVBOid = 0;\n\tattachAttribute(pShader->l_aPos, 3, &pDJ->aPos);\n\tattachAttribute(pShader->l_aTuv, 2, &pDJ->aTuv);\n\n\tif (pDJ->glEBOid > 0)\n\t\tglBindBuffer(GL_ELEMENT_ARRAY_BUFFER, pDJ->glEBOid);\n\n\tglBindVertexArray(0);\n\tglBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);\n\tglBindBuffer(GL_ARRAY_BUFFER, 0);\n\treturn 1;\n}\n\nint DrawJob::attachAttribute(int varLocationInShader, int attributeSizeInFloats, AttribRef* pAR) {\n\tif (varLocationInShader < 0)\n\t\treturn 0; \/\/not used in this shader\n\tif (pAR->glVBOid == 0) {\n\t\tmylog("ERROR in DrawJob::attachAttribute, nk such attribute\/VBO\\n");\n\t\treturn -1;\n\t}\n\tglEnableVertexAttribArray(varLocationInShader);\n\tif (activeVBOid != pAR->glVBOid) {\n\t\tactiveVBOid = pAR->glVBOid;\n\t\t\/\/attach input stream data\n\t\tglBindBuffer(GL_ARRAY_BUFFER, activeVBOid);\n\t}\n\tglVertexAttribPointer(varLocationInShader, attributeSizeInFloats, GL_FLOAT, GL_FALSE, pAR->stride, (void*)(long)pAR->offset);\n\treturn 1;\n}\nint DrawJob::executeDrawJob(DrawJob* pDJ, float* uMVP, Material* pMt) {\n\tif (pMt == NULL)\n\t\tpMt = &(pDJ->mt);\n\tglBindVertexArray(pDJ->glVAOid);\n\tShader* pShader = Shader::shaders.at(pMt->shaderN);\n\tglUseProgram(pShader->GLid);\n\tglUniformMatrix4fv(pShader->l_uMVP, 1, GL_FALSE, (const GLfloat*)uMVP);\n\n\t\/\/attach textures\n\tif (pShader->l_uTex0 >= 0) {\n\t\tint textureId = Texture::getGLid(pMt->uTex0);\n\t\t\/\/pass textureId to shader program\n\t\tglActiveTexture(GL_TEXTURE0); \/\/ activate the texture unit first before binding texture\n\t\tglBindTexture(GL_TEXTURE_2D, textureId);\n\t\t\/\/ Tell the texture uniform sampler to use this texture in the shader by binding to texture unit 0. \n\t\tglUniform1i(pShader->l_uTex0, 0);\n\t}\n\t\/\/other uniforms\n\tif (pShader->l_uColor >= 0) {\n\t\t\/\/float uColor[4] = { 1.f, 0.f, 1.f, 1.f }; \/\/R,G,B, alpha\n\t\tglUniform4fv(pShader->l_uColor, 1, pMt->uColor.forGL());\n\t}\n\tif (pDJ->glEBOid == 0) {\n\t\tglDrawArrays(pMt->primitiveType, 0, pDJ->pointsN);\n\t}\n\telse { \/\/use EBO\n\t\tglDrawElements(pMt->primitiveType, pDJ->pointsN, GL_UNSIGNED_SHORT, 0);\n\t}\n\tglBindVertexArray(0);\n\treturn 1;\n}\nint DrawJob::cleanUp() {\n\tint itemsN = drawJobs.size();\n\t\/\/delete all drawJobs\n\tfor (int i = 0; i < itemsN; i++) {\n\t\tDrawJob* pDJ = drawJobs.at(i);\n\t\tdelete pDJ;\n\t}\n\tdrawJobs.clear();\n\t\/\/delete Buffers\n\titemsN = buffersIds.size();\n\t\/\/delete all buffers\n\tfor (int i = 0; i < itemsN; i++) {\n\t\tunsigned int id = buffersIds.at(i);\n\t\tglDeleteBuffers(1, &id);\n\t}\n\tbuffersIds.clear();\n\n\treturn 1;\n}\nint DrawJob::setDesirableOffsetsForSingleVBO(DrawJob* pDJ, int* pStride, int shaderN, int VBOid) {\n\t\/\/sets desirable offsets and stride according to given shader needs\n\t\/\/assuming that we have 1 single VBO\n\tShader* pSh = Shader::shaders.at(shaderN);\n\tint stride = 0;\n\tpDJ->aPos.offset = 0; \/\/attribute o_aPos, always 0\n\tstride += sizeof(float) * 3; \/\/aPos size - 3 floats (x,y,z)\n\tif (pSh->l_aTuv >= 0) { \/\/attribute TUV (texture coordinates)\n\t\tpDJ->aTuv.offset = stride; \/\/attribute TUV (texture coordinates)\n\t\tstride += sizeof(float) * 2;\n\t}\n\t*pStride = stride;\n\t\/\/add stride and VBOid to all attributes\n\tAttribRef* pAR = NULL;\n\tpAR = &pDJ->aPos; pAR->glVBOid = VBOid; pAR->stride = stride;\n\tpAR = &pDJ->aTuv; pAR->glVBOid = VBOid; pAR->stride = stride;\n\n\treturn 1;\n}\n\n<\/pre><\/div>\n\n\n
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