Rebuild EVS app with richer feature set

Adds support for additional data formats, multiple cameras, and lays the
foundation for GL rendered overlays.

Test: build and run on Gordon Peak with Logitech USB camera
Change-Id: I60403361a91593d4e387df67a563522547efa981

1 files changed, 198 insertions, 0 deletions

diff --git a/evs/app/TexWrapper.cpp b/evs/app/TexWrapper.cpp
new file mode 100644
index 0000000000..7ec2191ff7
--- /dev/null
+++ b/evs/app/TexWrapper.cpp
@@ -0,0 +1,198 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "TexWrapper.h"
+#include "glError.h"
+
+#include "log/log.h"
+
+#include <fcntl.h>
+#include <malloc.h>
+#include <png.h>
+
+
+/* Create an new empty GL texture that will be filled later */
+TexWrapper::TexWrapper() {
+    GLuint textureId;
+    glGenTextures(1, &textureId);
+    if (textureId <= 0) {
+        ALOGE("Didn't get a texture handle allocated: %s", getEGLError());
+    } else {
+        // Store the basic texture properties
+        id = textureId;
+        w  = 0;
+        h  = 0;
+    }
+}
+
+
+/* Wrap a texture that already allocated.  The wrapper takes ownership. */
+TexWrapper::TexWrapper(GLuint textureId, unsigned width, unsigned height) {
+    // Store the basic texture properties
+    id = textureId;
+    w  = width;
+    h  = height;
+}
+
+
+TexWrapper::~TexWrapper() {
+    // Give the texture ID back
+    if (id > 0) {
+        glDeleteTextures(1, &id);
+    }
+    id = -1;
+}
+
+
+/* Factory to build TexWrapper objects from a given PNG file */
+TexWrapper* createTextureFromPng(const char * filename)
+{
+    // Open the PNG file
+    FILE *inputFile = fopen(filename, "rb");
+    if (inputFile == 0)
+    {
+        perror(filename);
+        return nullptr;
+    }
+
+    // Read the file header and validate that it is a PNG
+    static const int kSigSize = 8;
+    png_byte header[kSigSize] = {0};
+    fread(header, 1, kSigSize, inputFile);
+    if (png_sig_cmp(header, 0, kSigSize)) {
+        printf("%s is not a PNG.\n", filename);
+        fclose(inputFile);
+        return nullptr;
+    }
+
+    // Set up our control structure
+    png_structp pngControl = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
+    if (!pngControl)
+    {
+        printf("png_create_read_struct failed.\n");
+        fclose(inputFile);
+        return nullptr;
+    }
+
+    // Set up our image info structure
+    png_infop pngInfo = png_create_info_struct(pngControl);
+    if (!pngInfo)
+    {
+        printf("error: png_create_info_struct returned 0.\n");
+        png_destroy_read_struct(&pngControl, nullptr, nullptr);
+        fclose(inputFile);
+        return nullptr;
+    }
+
+    // Install an error handler
+    if (setjmp(png_jmpbuf(pngControl))) {
+        printf("libpng reported an error\n");
+        png_destroy_read_struct(&pngControl, &pngInfo, nullptr);
+        fclose(inputFile);
+        return nullptr;
+    }
+
+    // Set up the png reader and fetch the remaining bits of the header
+    png_init_io(pngControl, inputFile);
+    png_set_sig_bytes(pngControl, kSigSize);
+    png_read_info(pngControl, pngInfo);
+
+    // Get basic information about the PNG we're reading
+    int bitDepth;
+    int colorFormat;
+    png_uint_32 width;
+    png_uint_32 height;
+    png_get_IHDR(pngControl, pngInfo,
+                 &width, &height,
+                 &bitDepth, &colorFormat,
+                 NULL, NULL, NULL);
+
+    GLint format;
+    switch(colorFormat)
+    {
+        case PNG_COLOR_TYPE_RGB:
+            format = GL_RGB;
+            break;
+        case PNG_COLOR_TYPE_RGB_ALPHA:
+            format = GL_RGBA;
+            break;
+        default:
+            printf("%s: Unknown libpng color format %d.\n", filename, colorFormat);
+            return nullptr;
+    }
+
+    // Refresh the values in the png info struct in case any transformation shave been applied.
+    png_read_update_info(pngControl, pngInfo);
+    int stride = png_get_rowbytes(pngControl, pngInfo);
+    stride += 3 - ((stride-1) % 4);   // glTexImage2d requires rows to be 4-byte aligned
+
+    // Allocate storage for the pixel data
+    png_byte * buffer = (png_byte*)malloc(stride * height);
+    if (buffer == NULL)
+    {
+        printf("error: could not allocate memory for PNG image data\n");
+        png_destroy_read_struct(&pngControl, &pngInfo, nullptr);
+        fclose(inputFile);
+        return nullptr;
+    }
+
+    // libpng needs an array of pointers into the image data for each row
+    png_byte ** rowPointers = (png_byte**)malloc(height * sizeof(png_byte*));
+    if (rowPointers == NULL)
+    {
+        printf("Failed to allocate temporary row pointers\n");
+        png_destroy_read_struct(&pngControl, &pngInfo, nullptr);
+        free(buffer);
+        fclose(inputFile);
+        return nullptr;
+    }
+    for (unsigned int r = 0; r < height; r++)
+    {
+        rowPointers[r] = buffer + r*stride;
+    }
+
+
+    // Read in the actual image bytes
+    png_read_image(pngControl, rowPointers);
+    png_read_end(pngControl, nullptr);
+
+
+    // Set up the OpenGL texture to contain this image
+    GLuint textureId;
+    glGenTextures(1, &textureId);
+    glBindTexture(GL_TEXTURE_2D, textureId);
+
+    // Send the image data to GL
+    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
+
+    // Initialize the sampling properties (it seems the sample may not work if this isn't done)
+    // The user of this texture may very well want to set their own filtering, but we're going
+    // to pay the (minor) price of setting this up for them to avoid the dreaded "black image" if
+    // they forget.
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+
+    // clean up
+    png_destroy_read_struct(&pngControl, &pngInfo, nullptr);
+    free(buffer);
+    free(rowPointers);
+    fclose(inputFile);
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+
+
+    // Return the texture
+    return new TexWrapper(textureId, width, height);
+}